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\begin{document}

\title{The Chirality of Isotopomers of Glycine Compared using Next-Generation
QTAIM}



\author[1]{Xing Nie}%
\author[1]{Yong Yang}%
\author[1]{Tianlv Xu}%
\author[2]{Malgorzata Biczysko}%
\author[1]{Steven Kirk}%
\author[1]{Samantha Jenkins}%
\affil[1]{Hunan Normal University}%
\affil[2]{Shanghai University}%


\vspace{-1em}



  
  \date{May 24, 2024}


\begingroup
\let\center\flushleft
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\selectlanguage{english}
\begin{abstract}
The effect of the presence of a deuterium (D) or tritium (T) isotope
bonded to the alpha carbon of glycine is determined without the need to
apply external forces e.g. electric fields or using normal mode
analysis. Isotopic effects were accounted for using the mass-dependent
diagonal Born-Oppenheimer energy correction (DBOC) at the CCSD level of
theory. We calculated the stress tensor trajectories of the dominant C-N
bond within next generation quantum theory of atoms in molecules
(NG-QTAIM). S-character chirality was discovered using the stress tensor
trajectories, instead of the Cahn--Ingold--Prelog (CIP) rules, for
ordinary glycine. The S-character chirality was preserved after the
substitution of the H on the alpha carbon for a D isotope but
transformed to R-character chirality after replacement with the T
isotope. This reversal of the chirality depending on the presence of a
single D or T isotope bound to the alpha carbon adds to the debate on
the nature of the extraterrestrial origins of chirality in simple amino
acids. We demonstrate that NG-QTAIM is a promising tool for
understanding isotopic induced electronic charge density changes, useful
in analysis of infrared (IR) or circular dichroism (CD) spectra
explaining changes in mode couplings and bands intensities or sign.%
\end{abstract}%



\sloppy


\textbf{The Chirality of Isotopomers of Glycine Compared using
Next-Generation QTAIM}

\textbf{Xing Nie\textsuperscript{1}, Yong Yang\textsuperscript{1},
Tianlv Xu\textsuperscript{1}, Malgorzata Biczysko\textsuperscript{2},
Steven R. Kirk\textsuperscript{1*} and Samantha
Jenkins\textsuperscript{1*}}

\emph{\textsuperscript{1}Key Laboratory of Chemical Biology and
Traditional Chinese Medicine Research and Key Laboratory of Resource
National and Local Joint Engineering Laboratory for New Petro-chemical
Materials and Fine Utilization of Resources, College of Chemistry and
Chemical Engineering, Hunan Normal University, Changsha, Hunan 410081,
China; niexing0623@foxmail.com (X N); yy0801@foxmail.com (Y Y);
xutl@hunnu.edu.cn (T X)}

\emph{\textsuperscript{2}International Centre for Quantum and Molecular
Structures,1/F Building E,Shanghai University, 99 Shangda Road,
Shanghai, 200444 China}

email: samanthajsuman@gmail.com

email: steven.kirk@cantab.net

The effect of the presence of a deuterium (D) or tritium (T) isotope
bonded to the alpha carbon of glycine is determined without the need to
apply external forces e.g. electric fields or using normal mode
analysis. Isotopic effects were accounted for using the mass-dependent
diagonal Born-Oppenheimer energy correction (DBOC) at the CCSD level of
theory. We calculated the stress tensor trajectories of the dominant C-N
bond within next generation quantum theory of atoms in molecules
(NG-QTAIM). S-character chirality was discovered using the stress tensor
trajectories, instead of the Cahn--Ingold--Prelog (CIP) rules, for
ordinary glycine. The S-character chirality was preserved after the
substitution of the H on the alpha carbon for a D isotope but
transformed to R-character chirality after replacement with the T
isotope. This reversal of the chirality depending on the presence of a
single D or T isotope bound to the alpha carbon adds to the debate on
the nature of the extraterrestrial origins of chirality in simple amino
acids. We demonstrate that NG-QTAIM is a promising tool for
understanding isotopic induced electronic charge density changes, useful
in analysis of infrared (IR) or circular dichroism (CD) spectra
explaining changes in mode couplings and bands intensities or sign.

1. Introduction

Isotopes, homo-electronic nuclei, showing distinct properties due to the
different nuclear spins\textsuperscript{1,2}, are omnipresent in the
universe\textsuperscript{3}. Traditionally, different properties have
been associated with the mass difference and observed for instance in
the variation of rate or equilibrium constant of two reactions (i.e.
kinetic isotope effect or a thermodynamic isotope
effect\textsuperscript{4}. In principle, isotopes can occur independent
of mass and spin because of symmetry restrictions on the molecular
wavefunction leading to different symmetry selection rules for different
isotopomers\textsuperscript{5}. In this work we refer to the isotopic
effect as a change of any property between molecules with distinct
isotopic components (isotopomers). Nevertheless, the isotopic effects
related to the lightest elements are most pronounced. The natural
abundance of atomic isotopes is then reflected in the isotopic
composition of molecules, but the artificial isotopic substitution--
mainly of hydrogen (H) to deuterium (D) has been used in many
applications. One group of applications is related to the identification
of species, or elucidation of molecular structures, by enhancing the
amount of available experimental data (in mass spectrometry, optical
spectroscopies, nuclear magnetic resonance (NMR)
spectroscopy)\textsuperscript{6--8}. Alternatively, isotopic labeling
allows one to mark and distinguish between specific parts of molecular
systems, for instance in biomolecular chemistry and deuterium labeling
for reaction analysis\textsuperscript{9--15}. Among the isotopic
substitutions of particular interest are those which change formally
achiral molecules into chiral ones. Such newly created species can then
be recognized by chiroptical spectroscopies, while Quack and co-workers
reported the first quantitative investigations of a ground-state energy
difference for the enantiomers of molecules that are chiral only by
isotopic substitution\textsuperscript{16}.

The origins of chiral molecules in space and its relation with the
chiral asymmetry of life on the Earth still remains a
mystery\textsuperscript{17}. So far the only chiral molecule detected in
the interstellar medium (ISM) is methyl-oxirane, however as it was
identified by means of achiral (rotational) signals its enantiomeric
composition is unknown\textsuperscript{18}. D and L forms of amino acids
have been found in meteorites and comets, but L-enantiomeric excesses
have been also established \textsuperscript{17}. As the star-planet
formation regions are characterized by very high D/H ratio, contributing
significantly to the formation of heavier molecules\textsuperscript{19},
isotopically induced chirality maybe highly relevant in an astrochemical
context. Oba \emph{et. al} . reported experimental evidence of chiral
glycine formation by the surface reaction of normal glycine in solid
form with deuterium atoms at conditions simulating interstellar
molecular clouds\textsuperscript{20}. Chiral glycine is a known chiral
trigger for amplifying an enantiomeric excess under certain
conditions\textsuperscript{21}: these results add to the long standing
debate on the origin of homochirality. The investigation of
Kawasaki\emph{et. al} . discovered that achiral meteoritic amino acids
that included glycine with hydrogen isotope (D/H) chirality were the
source of chirality in asymmetric autocatalysis with amplification of
enantiomeric excess to enable the creation of highly enantioenriched
5-pyrimidyl alkanols\textsuperscript{21}. Kawasaki \emph{et. al} found
that the chirality of the S and R enantiomers was mainly attributable to
the very small difference between the C-D and C-H bond-lengths
associated with the alpha carbon of glycine\textsuperscript{21--23}. The
development of a highly sensitive method for the detection of isotopic
chirality in meteoritic organic compounds such as amino
acids\textsuperscript{24} with an achiral framework and isotopic
enrichment therefore remains a challenging subject\textsuperscript{25}.

The unknown chirality-helicity equivalence, that associates chirality
with a helical characteristic, was recently located although not
quantified by some of the current authors\textsuperscript{26} and was
used to distinguish the S and R stereoisomers of lactic acid in
agreement with the naming schemes from optical experiments. Some of the
current authors have very recently published the derivation of the
chirality-helicity equivalence that quantifies the chiral character in
formally achiral species\textsuperscript{27}. Consistency with our work
was found from experiments by Beaulieu \emph{et al.} on neutral
molecules\textsuperscript{28} that utilize coherent helical motion of
bound electrons. Abstract chirality measures for non-rigid objects have
been used to associate optical rotation with the structure of a
molecule\textsuperscript{29}.

Within the Born-Oppenheimer (B.O.) approximation the electronic spectra
of isotopomers are identical because the electronic
Hamiltonian\({\hat{H}}_{e}\) in the BO approximation is not dependent
on nuclear masses despite differences in their nuclei dynamics.
Therefore isotope sensitivity is typically achieved via nuclear
dynamics, for example by considering vibrational spectra. In this
contribution we explore the effect of non-adiabatic coupling corrections
and find that despite subtle differences that they induce in geometries
those differences are sufficient to be reliably captured by non-scalar
QTAIM quantities.\selectlanguage{english}
\begin{figure}[H]
\begin{center}
\includegraphics[width=0.70\columnwidth]{figures/image1/image1}

\end{center}
\end{figure}

\textbf{Scheme 1.} The molecular graph of the singly deuterated and
triterated isotopomers substituted onto the (alpha carbon) C1 atom of
glycine: S\textsubscript{a} (X3 = D3/T3, X10 = H10) (left panel) and
R\textsubscript{a} (X3 = H3, X10 = D10/T10) (right panel). The notation
HH will be used to denote X3 = H3, X10 = H10. The following notation HD
is used for \{S\textsubscript{a} (X3 = D3, X10 = H10),
R\textsubscript{a} (X3 = H3, X10 = D10)\} and HT is denotes
\{S\textsubscript{a} (X3 = T3, X10 = H10), R\textsubscript{a} (X3 = H3,
X10 = T10)\}. The torsional C1-C2 \emph{BCP} and torsional
C1-N7\emph{BCP} are indicated by the black and blue circles
respectively, where the undecorated green spheres indicated the
locations of bond critical points (\emph{BCPs} ).

In this article, we thus explore the extent to which subtle differences
between the electronic structures of isotopomers can be captured by
directly analyzing the electron density rather than by referring to the
vibrational spectrum. Tritium is a spin-\selectlanguage{ngerman}½ isotope of hydrogen, with
effectively the same chemical shifts but with slightly higher
sensitivity, dispersion and coupling constants\textsuperscript{30}.

We consider the total electronic charge density because it is an
observable\textsuperscript{31--33}, rather than the wavefunction which
is not. Total electronic charge density distributions are available even
when sharp spectral lines are not such as is the case for the solid
state. We will analyze density-dependent quantities of the deuterium and
tritium isotopomers of glycine using QTAIM (Quantum Theory of Atoms in
Molecules)\textsuperscript{34} and more specifically the directional
next generation QTAIM see \textbf{Scheme 1} . Previously, the stress
tensor trajectories T(\emph{s} ), within Next generation QTAIM, were
used to quantify the O-H bond-flexing, bond-torsion and bond-axiality
(formerly referred to as bond anharmonicity) contributions to be
compared for different isotopomers of normal modes of the water
molecule\textsuperscript{35}. This earlier analysis enabled the coupling
of intramolecular vibrational modes to be assessed and compared,
particularly between the bending normal mode and the symmetric-stretch
normal modes. The glycine conformer selected for current investigation
is characterized by an intense IR band\textsuperscript{36} involving the
C2-O5-H6 bending coupled with the wagging vibration of methylene group
(C1X3X10)\textsuperscript{37}, which is expected to be shifted by D/T
isotopic substitution at that alpha carbon (C1), see \textbf{Scheme 1} .
The ability to capture the chiral character and its changes upon the D/T
substitution allows the direct analysis of differences in the
chiroptical spectra. Such changes include sign changes, without the need
to introduce approximations based on the normal modes
description\textsuperscript{38}.

\textbf{2. Theoretical Background}

The interested reader is referred to the complete mathematical
expressions and explanations in the \textbf{Supplementary Materials S1}
. QTAIM analysis\textsuperscript{39--45} is used to
identify\emph{critical points} in the total electronic charge density
distribution \selectlanguage{greek}\emph{ρ} \selectlanguage{english}(\textbf{r} ) where the gradient vector field
[?]\selectlanguage{greek}\emph{ρ} \selectlanguage{english}(\textbf{r} ) = 0. There are four distinct categories of
critical points according to the set of ordered eigenvalues
\selectlanguage{greek}λ\selectlanguage{english}\textsubscript{1} \textless{} \selectlanguage{greek}λ\selectlanguage{english}\textsubscript{2} \textless{}
\selectlanguage{greek}λ\selectlanguage{english}\textsubscript{3}, with the associated set of eigenvectors
(\emph{e}\textsubscript{\textbf{1}} , \emph{e}\textsubscript{\textbf{2}}
,\emph{e}\textsubscript{\textbf{3}} ), of the Hessian matrix of the
electronic charge density, \selectlanguage{greek}\emph{ρ} \selectlanguage{english}(\textbf{r} ), defined as the matrix
of partial second derivatives with respect to the spatial coordinates,
[?]:[?]\selectlanguage{greek}\emph{ρ} \selectlanguage{english}(\textbf{r} ). Critical points are labeled using the
notation (\emph{R} , \selectlanguage{greek}ω\selectlanguage{english}) where \emph{R} is the rank of the Hessian matrix
and \selectlanguage{greek}ω \selectlanguage{english}is the signature; the (3, -3) {[}nuclear critical point
(\emph{NCP} ), a local maximum generally corresponding to a nuclear
location{]}, (3, -1) and (3, 1) {[}saddle points, called bond critical
points (\emph{BCP} ) and ring critical points (\emph{RCP} ),
respectively{]} and (3, 3) {[}the cage critical points (\emph{CCP} ){]}.
In this investigation we will only be considering bond critical points
(\emph{BCP} s).

The ellipticity \selectlanguage{greek}ε, \selectlanguage{english}quantifies the relative accumulation of\selectlanguage{greek}\emph{ρ}
\selectlanguage{english}(\textbf{r \textsubscript{b})} in the two
directions\textbf{(\emph{e}\textsubscript{1}}
and\emph{e}\textsubscript{\textbf{2}}\textbf{)} perpendicular to the
bond-path at r\textsubscript{b}. For ellipticity values \textgreater{}
0, the associated \selectlanguage{greek}λ\selectlanguage{english}\textsubscript{1} and \selectlanguage{greek}λ\selectlanguage{english}\textsubscript{2} Hessian
eigenvalues correspond to the shortest and longest axes of the
elliptical distribution of \selectlanguage{greek}\emph{ρ} \selectlanguage{english}\textbf{(r\textsubscript{b}} ),
respectively.

Bond-flexing distortions involve the stretching of a bond (bond-path) so
that the bond-path length (BPL) exceeds the bonded inter-nuclear
geometric separation distance. A shift of a \emph{BCP} position along
the containing bond-path due to changes to bonded inter-nuclear
separations results in the presence of \emph{BCP} sliding. As a
consequence of this \emph{BCP} sliding the chemical nature of the bond
is dependent on the relative position of the \emph{BCP} , i.e. we can
quantify a degree of bond-axiality\textsuperscript{35}. The construction
of the stress tensor trajectories T\selectlanguage{greek}\textsubscript{σ}\selectlanguage{english}(s ) involves the
required additional symmetry breaking to identify chirality in the form
of the \emph{e}\selectlanguage{greek}\textsubscript{\textbf{3σ}} \selectlanguage{english}eigenvector. This enables the
T\selectlanguage{greek}\textsubscript{σ}\selectlanguage{english}(s ) corresponding to the counterclockwise (CCW) and
clockwise (CW) directions of torsion to be distinguished even for the
highly symmetrically positioned torsional C1-C2 \emph{BCP} , see
\textbf{Scheme 1} . To be consistent with optical experiments as
previously undertaken\textsuperscript{46} we
define\selectlanguage{greek}\textbf{S\textsubscript{σ}} \selectlanguage{english}(left-handed) character to be dominant
over\textbf{R} \selectlanguage{greek}\textsubscript{σ} \selectlanguage{english}character (right-handed) for values of
the chirality C\selectlanguage{greek}\textsubscript{σ} \selectlanguage{english}(CCW) \textgreater{} (CW) since CCW and
CW represent left and right handed directions of torsion respectively.
Note the use of the subscript ``\selectlanguage{greek}\textsubscript{σ}\selectlanguage{english}'' because we are using
the stress tensor T\selectlanguage{greek}\textsubscript{σ}\selectlanguage{english}(s ) in the stress tensor
U\selectlanguage{greek}\textsubscript{σ}-\selectlanguage{english}space. The chirality C\selectlanguage{greek}\textsubscript{σ} \selectlanguage{english}of a torsion
bond (in this work the torsional C1-C2 \emph{BCP} and torsional
C1-N7\emph{BCP} ) is defined by the difference in the maximum
T\selectlanguage{greek}\textsubscript{σ}\selectlanguage{english}(\emph{s} ) projections (the dot product of the stress
tensor \selectlanguage{greek}\textbf{e\textsubscript{1σ}} \selectlanguage{english}eigenvector and the \emph{BCP}
shift\textbf{dr} ) of the T\selectlanguage{greek}\textsubscript{σ}\selectlanguage{english}(s ) values between the CCW
and CW torsions:

C\selectlanguage{greek}\textsubscript{σ} \selectlanguage{english}=
{[}\selectlanguage{greek}\textbf{(e\textsubscript{1σ}[?]dr)\textsubscript{max}}\selectlanguage{english}
{]}\textsubscript{\textbf{CCW}}-
{[}\selectlanguage{greek}\textbf{(e\textsubscript{1σ}[?]dr)\textsubscript{max}}\selectlanguage{english}
{]}\textsubscript{\textbf{CW}}(\textbf{1)}

These torsions correspond to the CW (-180.0\selectlanguage{ngerman}° \selectlanguage{english}[?] \selectlanguage{greek}θ \selectlanguage{english}[?] \selectlanguage{english}0.0\selectlanguage{ngerman}°) and CCW (0° \selectlanguage{english}[?] \selectlanguage{greek}θ
\selectlanguage{english}[?] \selectlanguage{english}180.0\selectlanguage{ngerman}°) directions of the torsion \selectlanguage{greek}θ. \selectlanguage{english}The chirality
C\selectlanguage{greek}\textsubscript{σ}\selectlanguage{english}quantifies the bond torsion direction CCW vs. CW, i.e.
\emph{circular}motion, since \selectlanguage{greek}\textbf{e\textsubscript{1σ}} \selectlanguage{english}is the most
preferred direction of charge density \selectlanguage{greek}\emph{ρ}
\selectlanguage{english}(\textbf{r\textsubscript{b}} ) accumulation.

The response of the C-H/D/T bonds to the CCW vs. CW torsions uses
equation \textbf{1(a)} but does not define a chirality
C\selectlanguage{greek}\textsubscript{σ} \selectlanguage{english}associated with a torsional bond of a molecule.
Instead the response is referred to as the bond-twist T\selectlanguage{greek}\textsubscript{σ}

\selectlanguage{english}The least preferred (\selectlanguage{greek}\textbf{e\textsubscript{2σ}} \selectlanguage{english}) direction of\selectlanguage{greek}\emph{ρ}
\selectlanguage{english}(\textbf{r\textsubscript{b}} ) corresponds to a more `difficult' bond
distortion than bond torsion, that we refer to as the bond-flexing
F\selectlanguage{greek}\textsubscript{σ} \selectlanguage{english}that is defined as:

F\selectlanguage{greek}\textsubscript{σ} \selectlanguage{english}=
{[}\selectlanguage{greek}\textbf{(e\textsubscript{2σ}[?]dr)\textsubscript{max}}\selectlanguage{english}
{]}\textsubscript{\textbf{CCW}}-
{[}\selectlanguage{greek}\textbf{(e\textsubscript{2σ}[?]dr)\textsubscript{max}}\selectlanguage{english}
{]}\textsubscript{\textbf{CW}}

\textbf{(2)}

The bond-axiality A\selectlanguage{greek}\textsubscript{σ} \selectlanguage{english}quantifies the resultant
\emph{BCP}motion along the bond-path, that coincides with
the\selectlanguage{greek}\textbf{e\textsubscript{3σ}} \selectlanguage{english}direction, that we refer to as the
bond-axial direction. The bond-axiality A\selectlanguage{greek}\textsubscript{σ} \selectlanguage{english}provides a
measure of symmetry breaking \textsuperscript{35} in response to the
bond torsion directions (CCW vs. CW). The bond-axiality
A\selectlanguage{greek}\textsubscript{σ} \selectlanguage{english}is defined as:

A\selectlanguage{greek}\textsubscript{σ} \selectlanguage{english}=
{[}\selectlanguage{greek}\textbf{(e\textsubscript{3σ}[?]dr)\textsubscript{max}}\selectlanguage{english}
{]}\textsubscript{\textbf{CCW}}-
{[}\selectlanguage{greek}\textbf{(e\textsubscript{3σ}[?]dr)\textsubscript{max}}\selectlanguage{english}
{]}\textsubscript{\textbf{CW}}

\textbf{(3)}

The sign (\selectlanguage{ngerman}±) of the chirality C\selectlanguage{greek}\textsubscript{σ}, \selectlanguage{english}bond twist
T\selectlanguage{greek}\textsubscript{σ} \selectlanguage{english}and bond-axiality A\selectlanguage{greek}\textsubscript{σ} \selectlanguage{english}determines the
dominance of \selectlanguage{greek}\textbf{S\textsubscript{σ}}
\selectlanguage{english}(C\selectlanguage{greek}\textsubscript{σ}\selectlanguage{english}\textgreater{} 0) and \selectlanguage{greek}\textbf{R\textsubscript{σ}}
\selectlanguage{english}(C\selectlanguage{greek}\textsubscript{σ}\selectlanguage{english}\textless{} 0) character. A high degree of
bond-axiality A\selectlanguage{greek}\textsubscript{σ} \selectlanguage{english}corresponds to a large difference in
the value of
the\selectlanguage{greek}\textbf{\{\emph{e}\textsubscript{3σ}.dr\}\textsubscript{max}}\selectlanguage{english} for the
CCW and CW torsion directions.

The stereoisomeric excess X\selectlanguage{greek}\textsubscript{σ} \selectlanguage{english}is defined as the ratio of
the magnitude of the C\selectlanguage{greek}\textsubscript{σ} \selectlanguage{english}values of the
S\textsubscript{a}and R\textsubscript{a} stereoisomers of the torsional
C1-N7 \emph{BCP}and represents the Next generation QTAIM interpretation
of the enantiomeric excess.

\textbf{3. Computational Details}

Isotopically substituted and unsubstituted molecular structures were
first geometry-optimized to an energy minimum. The 6-311(2d,3p) basis
set was selected and was used consistently in the geometry optimizations
and all subsequent single-point calculations. Isotopic effects were
included by performing the geometry optimization using a
finite-difference approach using energies alone, calculated with the
mass-dependent diagonal Born-Oppenheimer energy correction
(DBOC)\textsuperscript{47,48} applied. This was carried out at the CCSD
level of theory using the CFOUR code\textsuperscript{49} , with the
following tight convergence criteria (in atomic units): Maximum
coupled-cluster amplitude change \textgreater{} 10\textsuperscript{-10},
RMS energy gradient \textless{} 10\textsuperscript{-5}, smallest linear
equation (DIIS) residual \textless{} 10\textsuperscript{-10} and
integrals tolerance 10\textsuperscript{-15}.

Torsional scans (using constrained geometry optimization) were then made
based on the converged structures from the previous step, with the C1
atom position coordinates and the C1-(H,D,T)3 and C1-(H,D,T)10 bond
lengths constrained to their previously converged energy minimum values,
using the B3LYP DFT functional, very tight geometry convergence criteria
and an 'ultrafine' grid for the DFT integrals as implemented in the G09
vE.01\textsuperscript{50} code. The full optimization Hessian was
recalculated at every optimization step. Finally, single-point
wavefunction calculations were run using G09, the same DFT functional,
basis set and integral parameters, with the SCF convergence criteria
\textless{} 10\textsuperscript{-10} RMS change in the density matrix,
and the corresponding wavefunctions analysed using
AIMAll\textsuperscript{51}. Next generation QTAIM analyses for
U\selectlanguage{greek}\textsubscript{σ}-\selectlanguage{english}space trajectories and derived quantities were
calculated from the resulting molecular graphs and wavefunctions using
our in-house developed software package QuantVec (formerly
AIMPAC2-Suite)\textsuperscript{52}.

\textbf{4. Results and Discussion}

\emph{4.1. The insufficiency of scalar measures for determining
chirality and distinguishing stereoisomers}

Note we use the subscript ``\textsubscript{a}'' for the S and R
stereoisomers of glycine because glycine is formally achiral and the
stereoisomers are produced by the symmetry breaking effects of the
introduction of the D and T isotopomers to the alpha carbon (C1), where
the CIP rules were used to allocate the S\textsubscript{a} and
R\textsubscript{a} designations, see \textbf{Scheme 1} . The variation
of the (scalar) energies [?]\emph{E,} BPL and ellipticity values \selectlanguage{greek}ε
\selectlanguage{english}relative to \selectlanguage{greek}θ \selectlanguage{english}= 0.0\selectlanguage{ngerman}º, corresponding to the relaxed geometry of glycine,
of the CW (-180.0º \selectlanguage{english}[?] \selectlanguage{greek}θ \selectlanguage{english}[?] \selectlanguage{english}0.0\selectlanguage{ngerman}º) and CCW (0.0º \selectlanguage{english}[?] \selectlanguage{greek}θ \selectlanguage{english}[?] \selectlanguage{english}180.0\selectlanguage{ngerman}º) torsions
associated with the C1-C2 \emph{BCP} for the pure glycine and singly
deuterated and triterated glycine do not distinguish the isotopomers,
see\textbf{Figure 1(a-b)} . The corresponding results for the
C1-N7\emph{BCP} display a high degree of asymmetry with respect to the
torsion \selectlanguage{greek}θ, \selectlanguage{english}but do not distinguish between the isotopomers,
see\textbf{Figure 1(c-d)} . The variation of the energies [?]\emph{E}
relative to \selectlanguage{greek}θ \selectlanguage{english}= 0.0\selectlanguage{ngerman}º, associated with the C1-N7 \emph{BCP} and C1-C2
\emph{BCP} , demonstrates the greater strength of interaction of the
C1-N7 \emph{BCP}compared to the C1-C2 \emph{BCP} , compare the left
panels of\textbf{Figure 1(a-b)} with those of \textbf{Figure 1(c-d)} .
These include the distance measures for a torsion \selectlanguage{greek}θ \selectlanguage{english}= 0.0\selectlanguage{ngerman}º that indicate
that the C1-N7 \emph{BCP} is closer to the C1 atom (1.198 a.u.) than the
C1-C2 \emph{BCP} (1.393 a.u.). This asymmetry in the location of
the\emph{BCP} along the C1-N7 \emph{BCP} bond-path leads to an asymmetry
of the variation of the BPL, see the middle panels of \textbf{Figure
1(c-d)} and the \emph{BCP} ellipticity \selectlanguage{greek}ε, \selectlanguage{english}see the rights panels
of\textbf{Figure 1(c-d)} with the CCW and CW torsions. In particular,
the lower values of the C1-N7 \emph{BCP} ellipticity \selectlanguage{greek}ε \selectlanguage{english}for the CCW (0.0\selectlanguage{ngerman}º
\selectlanguage{english}[?] \selectlanguage{greek}θ \selectlanguage{english}[?] \selectlanguage{english}180.0\selectlanguage{ngerman}º) torsion compared to the CW (-180.0º \selectlanguage{english}[?] \selectlanguage{greek}θ \selectlanguage{english}[?] \selectlanguage{english}0.0\selectlanguage{ngerman}º) torsion
indicate a preference for the CCW torsion over the CW torsion. This is
because a bond with lower ellipticity \selectlanguage{greek}ε \selectlanguage{english}values, e.g. single bonds, will
undergo a torsion deformation more readily than bonds with a higher
ellipticity \selectlanguage{greek}ε \selectlanguage{english}value, as is the case for double bonds. The symmetrical
location of the C1-C2 \emph{BCP} mid-way along the associated bond-path
results in symmetrical variations of the BPL and the ellipticity \selectlanguage{greek}ε \selectlanguage{english}with
the CCW and CW torsions and hence no preferred direction of torsion, CCW
or CW, is indicated.

Considering the limitations of the scalar \emph{BCP} ellipticity \selectlanguage{greek}ε \selectlanguage{english}in
determining preferences of CCW over CW for the C1-C2 \emph{BCP} , we now
proceed to examine the directional differences between the CCW and CW
torsions of the torsional C1-N7 \emph{BCP} and C1-C2 \emph{BCP} with the
vector-based stress tensor trajectories T\selectlanguage{greek}\textsubscript{σ}\selectlanguage{english}(s),
see\textbf{Figure 1(c)} and \textbf{Figure 1(d)} respectively.
The\emph{BCP} ellipticity \selectlanguage{greek}ε \selectlanguage{english}does not take into account the bond-path
eigenvector (\emph{e}\selectlanguage{greek}\textsubscript{\textbf{3σ}} \selectlanguage{english}) and therefore cannot
quantify torsional CCW vs. CW preferences for a symmetrically positioned
C1-C2 \emph{BCP} , see \textbf{Figure 1(a-d)} .\selectlanguage{english}
\begin{figure}[H]
\begin{center}
\includegraphics[width=0.70\columnwidth]{figures/image5/image5}

\end{center}
\end{figure}\selectlanguage{english}
\begin{figure}[H]
\begin{center}
\includegraphics[width=0.70\columnwidth]{figures/image6/image6}

\end{center}
\end{figure}\selectlanguage{english}
\begin{figure}[H]
\begin{center}
\includegraphics[width=0.70\columnwidth]{figures/image7/image7}

\end{center}
\end{figure}

\textbf{(a)}\selectlanguage{english}
\begin{figure}[H]
\begin{center}
\includegraphics[width=0.70\columnwidth]{figures/image8/image8}

\end{center}
\end{figure}\selectlanguage{english}
\begin{figure}[H]
\begin{center}
\includegraphics[width=0.70\columnwidth]{figures/image9/image9}

\end{center}
\end{figure}\selectlanguage{english}
\begin{figure}[H]
\begin{center}
\includegraphics[width=0.70\columnwidth]{figures/image10/image10}

\end{center}
\end{figure}

\textbf{(b)}\selectlanguage{english}
\begin{figure}[H]
\begin{center}
\includegraphics[width=0.70\columnwidth]{figures/image11/image11}

\end{center}
\end{figure}\selectlanguage{english}
\begin{figure}[H]
\begin{center}
\includegraphics[width=0.70\columnwidth]{figures/image12/image12}

\end{center}
\end{figure}\selectlanguage{english}
\begin{figure}[H]
\begin{center}
\includegraphics[width=0.70\columnwidth]{figures/image13/image13}

\end{center}
\end{figure}

\textbf{(c)}\selectlanguage{english}
\begin{figure}[H]
\begin{center}
\includegraphics[width=0.70\columnwidth]{figures/image14/image14}

\end{center}
\end{figure}\selectlanguage{english}
\begin{figure}[H]
\begin{center}
\includegraphics[width=0.70\columnwidth]{figures/image15/image15}

\end{center}
\end{figure}\selectlanguage{english}
\begin{figure}[H]
\begin{center}
\includegraphics[width=0.70\columnwidth]{figures/image16/image16}

\end{center}
\end{figure}

\textbf{(d)}

\textbf{Figure 1.} The variation of the relative energy [?]\emph{E} of the
torsional C1-C2 \emph{BCP} with the CW (-180.0\selectlanguage{ngerman}º \selectlanguage{english}[?] \selectlanguage{greek}θ \selectlanguage{english}[?] \selectlanguage{english}0.0\selectlanguage{ngerman}º) and CCW
(0.0º \selectlanguage{english}[?] \selectlanguage{greek}θ \selectlanguage{english}[?] \selectlanguage{english}180.0\selectlanguage{ngerman}º) directions of torsion for (left panel), the
corresponding variations of the bond-path lengths (BPL) C1-C2
\emph{BCP}(middle panel) and the ellipticity \selectlanguage{greek}ε \selectlanguage{english}(right panel) of glycine
is presented in \textbf{Figure 1(a)} . The plots for the HD and HT
isotopomers and S\textsubscript{a} and R\textsubscript{a} stereoisomers
for the CW and CCW directions of the torsional C1-C2 \emph{BCP} of the
variation of the relative energy [?]\emph{E} (left panel), the variations
of the BPL (middle panel) and ellipticity \selectlanguage{greek}ε \selectlanguage{english}(right panel) are presented
in \textbf{Figure 1(b)} , also see the \textbf{Scheme 1} for further
details. The corresponding plots for the torsional C1-N7 \emph{BCP} are
presented in \textbf{Figure 1(c)} and \textbf{Figure 1(d)} respectively.

Differences in the distance measurements of the minimum energy
geometries only become apparent for the introduction of the deuterium
and tritium isotopes, see \textbf{Table 1(a-b)} .

\textbf{Table 1(a)} . The distance measures of the isotopomers (HH) of
glycine of the structures corresponding to the minimum energy. The
values of the inter-nuclear separations that are referred to as the
geometric bond-lengths (GBL) bond-path lengths (BPL) (in a.u.) and the
partial bond-lengths (C1/C2-\emph{BCP} , \emph{BCP} -H3). Note the BPL
\textless{} GBL due to the positions of the non-nuclear attractor (NNA)
and geometric centre not coinciding for the hydrogen atom.\selectlanguage{english}
\begin{longtable}[]{@{}llllll@{}}
\toprule
Isotopomer & \emph{GBL} & \emph{BPL} &
\textbf{(C1-\emph{BCP},\emph{BCP}-H3/H10)} &
\textbf{(C1-\emph{BCP},\emph{BCP}-C2)} &
\textbf{(C1-\emph{BCP},\emph{BCP}-N7)}\tabularnewline
\midrule
\endhead
\emph{HH} & & & & &\tabularnewline
C1-C2 & 2.8934 & 2.8927 & (---, ---) & (1.3929, 1.4999) & (---,
---)\tabularnewline
C1-N7 & 2.7389 & 2.7375 & (---, ---) & (---, ---) & (1.1980,
1.5402)\tabularnewline
C1-H3 & 2.0678 & 2.0360 & (1.3019, 0.7659) & (---, ---) & (---,
---)\tabularnewline
C1-H10 & 2.0678 & 2.0360 & (1.3019, 0.7659) & (---, ---) & (---,
---)\tabularnewline
\bottomrule
\end{longtable}

\textbf{Table 1(b).} The distance measures of the S\textsubscript{a} and
R\textsubscript{a} for the \emph{HD} and \emph{HT} isotopomers of
glycine for values of the torsion \selectlanguage{greek}θ \selectlanguage{english}= 0.0\selectlanguage{ngerman}º, see the caption
of\textbf{Table 1(a)} for further details.\selectlanguage{english}
\begin{longtable}[]{@{}lllllllllllllllll@{}}
\toprule
\begin{minipage}[b]{0.06\columnwidth}\raggedright\strut
Isotopomer\strut
\end{minipage} & \begin{minipage}[b]{0.06\columnwidth}\raggedright\strut
\textbf{GBL}\strut
\end{minipage} & \begin{minipage}[b]{0.06\columnwidth}\raggedright\strut
\textbf{BPL}\strut
\end{minipage} & \begin{minipage}[b]{0.06\columnwidth}\raggedright\strut
\textbf{BPL}\strut
\end{minipage} & \begin{minipage}[b]{0.06\columnwidth}\raggedright\strut
\textbf{(C1-\emph{BCP},} \emph{BCP}\textbf{-H3/} \textbf{D3/T3)}\strut
\end{minipage} & \begin{minipage}[b]{0.06\columnwidth}\raggedright\strut
\textbf{(C1-\emph{BCP},} \emph{BCP}\textbf{-H3/} \textbf{D3/T3)}\strut
\end{minipage} & \begin{minipage}[b]{0.06\columnwidth}\raggedright\strut
\textbf{(C1-\emph{BCP},} \emph{BCP}\textbf{-H10/}
\textbf{D10/T10)}\strut
\end{minipage} & \begin{minipage}[b]{0.06\columnwidth}\raggedright\strut
\textbf{(C1-\emph{BCP},} \emph{BCP}\textbf{-H10/}
\textbf{D10/T10)}\strut
\end{minipage} & \begin{minipage}[b]{0.06\columnwidth}\raggedright\strut
\textbf{(C1-\emph{BCP},} \emph{BCP}\textbf{-H10/}
\textbf{D10/T10)}\strut
\end{minipage} & \begin{minipage}[b]{0.06\columnwidth}\raggedright\strut
\textbf{(C1-\emph{BCP},} \emph{BCP}\textbf{-C2)}\strut
\end{minipage} & \begin{minipage}[b]{0.06\columnwidth}\raggedright\strut
\textbf{(C1-\emph{BCP},} \emph{BCP}\textbf{-C2)}\strut
\end{minipage} & \begin{minipage}[b]{0.06\columnwidth}\raggedright\strut
\textbf{(C1-\emph{BCP},} \emph{BCP}\textbf{-C2)}\strut
\end{minipage} & \begin{minipage}[b]{0.06\columnwidth}\raggedright\strut
\textbf{(C1-\emph{BCP},} \emph{BCP}\textbf{-N7)}\strut
\end{minipage} & \begin{minipage}[b]{0.06\columnwidth}\raggedright\strut
\textbf{(C1-\emph{BCP},} \emph{BCP}\textbf{-N7)}\strut
\end{minipage} & \begin{minipage}[b]{0.06\columnwidth}\raggedright\strut
\textbf{(C1-\emph{BCP},} \emph{BCP}\textbf{-N7)}\strut
\end{minipage} & \begin{minipage}[b]{0.06\columnwidth}\raggedright\strut
\textbf{(C1-\emph{BCP},} \emph{BCP}\textbf{-N7)}\strut
\end{minipage} & \begin{minipage}[b]{0.06\columnwidth}\raggedright\strut
\textbf{(C1-\emph{BCP},} \emph{BCP}\textbf{-N7)}\strut
\end{minipage}\tabularnewline
\midrule
\endhead
\begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
S\textsubscript{a} stereoisomer\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
S\textsubscript{a} stereoisomer\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
S\textsubscript{a} stereoisomer\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
S\textsubscript{a} stereoisomer\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
S\textsubscript{a} stereoisomer\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
S\textsubscript{a} stereoisomer\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
S\textsubscript{a} stereoisomer\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
S\textsubscript{a} stereoisomer\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
S\textsubscript{a} stereoisomer\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
S\textsubscript{a} stereoisomer\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
S\textsubscript{a} stereoisomer\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
S\textsubscript{a} stereoisomer\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
S\textsubscript{a} stereoisomer\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
S\textsubscript{a} stereoisomer\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
S\textsubscript{a} stereoisomer\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
S\textsubscript{a} stereoisomer\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
S\textsubscript{a} stereoisomer\strut
\end{minipage}\tabularnewline
\begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
\emph{HD}\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
\strut
\end{minipage}\tabularnewline
\begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
C1-C2\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
2.8868\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
2.8875\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
2.8875\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(1.3900, 1.4975)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(1.3900, 1.4975)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(1.3900, 1.4975)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(1.3900, 1.4975)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage}\tabularnewline
\begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
C1-N7\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
2.7355\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
2.7368\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
2.7368\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(1.1989, 1.5379)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(1.1989, 1.5379)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(1.1989, 1.5379)\strut
\end{minipage}\tabularnewline
\begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
C1-D3\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
2.0714\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
2.0397\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
2.0397\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(1.3051, 0.7345)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(1.3051, 0.7345)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(1.3051, 0.7345)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage}\tabularnewline
\begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
C1-H10\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
2.0713\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
2.0397\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
2.0397\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(1.3040, 0.7357)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(1.3040, 0.7357)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(1.3040, 0.7357)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage}\tabularnewline
\begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
\emph{HT}\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
\strut
\end{minipage}\tabularnewline
\begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
C1-C2\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
2.8914\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
2.8908\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
2.8908\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(1.3933, 1.4976)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(1.3933, 1.4976)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(1.3933, 1.4976)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(1.3933, 1.4976)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage}\tabularnewline
\begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
C1-N7\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
2.7407\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
2.7394\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
2.7394\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(1.2011, 1.5390)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(1.2011, 1.5390)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(1.2011, 1.5390)\strut
\end{minipage}\tabularnewline
\begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
C1-T3\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
2.0765\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
2.0449\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
2.0449\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(1.3089, 0.7676)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(1.3089, 0.7676)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(1.3089, 0.7676)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage}\tabularnewline
\begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
C1-H10\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
2.0742\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
2.0426\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
2.0426\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(1.3062, 0.7681)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(1.3062, 0.7681)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(1.3062, 0.7681)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage}\tabularnewline
\begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
R\textsubscript{a} stereoisomer\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
R\textsubscript{a} stereoisomer\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
R\textsubscript{a} stereoisomer\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
R\textsubscript{a} stereoisomer\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
R\textsubscript{a} stereoisomer\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
R\textsubscript{a} stereoisomer\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
R\textsubscript{a} stereoisomer\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
R\textsubscript{a} stereoisomer\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
R\textsubscript{a} stereoisomer\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
R\textsubscript{a} stereoisomer\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
R\textsubscript{a} stereoisomer\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
R\textsubscript{a} stereoisomer\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
R\textsubscript{a} stereoisomer\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
R\textsubscript{a} stereoisomer\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
R\textsubscript{a} stereoisomer\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
R\textsubscript{a} stereoisomer\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
R\textsubscript{a} stereoisomer\strut
\end{minipage}\tabularnewline
\begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
\emph{HD}\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
\strut
\end{minipage}\tabularnewline
\begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
C1-C2\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
2.8908\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
2.8914\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
2.8914\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(1.3935, 1.4980)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(1.3935, 1.4980)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(1.3935, 1.4980)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(1.3935, 1.4980)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage}\tabularnewline
\begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
C1-N7\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
2.7394\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
2.7407\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
2.7407\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(1.2015, 1.5392)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(1.2015, 1.5392)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(1.2015, 1.5392)\strut
\end{minipage}\tabularnewline
\begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
C1-H3\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
2.0742\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
2.0426\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
2.0426\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(1.3063, 0.7363)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(1.3063, 0.7363)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(1.3063, 0.7363)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage}\tabularnewline
\begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
C1-D10\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
2.0765\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
2.0449\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
2.0449\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(1.3091, 0.7359)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(1.3091, 0.7359)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(1.3091, 0.7359)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage}\tabularnewline
\begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
\emph{HT}\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
\strut
\end{minipage}\tabularnewline
\begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
C1-C2\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
2.8914\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
2.8908\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
2.8908\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(1.3933, 1.4976)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(1.3933, 1.4976)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(1.3933, 1.4976)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(1.3933, 1.4976)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage}\tabularnewline
\begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
C1-N7\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
2.7407\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
2.7394\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
2.7394\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(1.2011, 1.5390)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(1.2011, 1.5390)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(1.2011, 1.5390)\strut
\end{minipage}\tabularnewline
\begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
C1-H3\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
2.0742\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
2.0426\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
2.0426\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(1.3062, 0.7681)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(1.3062, 0.7681)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(1.3062, 0.7681)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage}\tabularnewline
\begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
C1-T10\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
2.0765\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
2.0449\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
2.0449\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(1.3089, 0.7676)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(1.3089, 0.7676)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(1.3089, 0.7676)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage} & \begin{minipage}[t]{0.04\columnwidth}\raggedright\strut
(---, ---)\strut
\end{minipage}\tabularnewline
\bottomrule
\end{longtable}

\emph{4.2. The stress tensor trajectories for the isotopomers of
formally achiral molecules}

The analysis for the dominant, i.e. the strongest torsional bond the
C1-N7 \emph{BCP} used to construct the chirality C\selectlanguage{greek}\textsubscript{σ},
\selectlanguage{english}bond-twist T\selectlanguage{greek}\textsubscript{σ}, \selectlanguage{english}bond-flexing F\selectlanguage{greek}\textsubscript{σ} \selectlanguage{english}and
bond-axiality A\selectlanguage{greek}\textsubscript{σ} \selectlanguage{english}is presented in \textbf{Figures 2-3}and
\textbf{Table 2(a-b)} and \textbf{Table 3(a-b)} . The geometries of the
torsional scans are provided in the \textbf{Supplementary Materials S2}
.

For the torsional C1-C2 \emph{BCP} the presence of non-overlapping
T\selectlanguage{greek}\textsubscript{σ}\selectlanguage{english}(s) for the CCW and CW torsions demonstrates the
uniqueness of the T\selectlanguage{greek}\textsubscript{σ}\selectlanguage{english}(s) given the highly symmetrical
positioning of the C1-C2 \emph{BCP} along the containing bond-path,
see\textbf{Scheme 1} and \textbf{Figures S3} of the
\textbf{Supplementary Materials S3} . The stress tensor trajectories
T\selectlanguage{greek}\textsubscript{σ}\selectlanguage{english}(s) of the torsional C1-C2 \emph{BCP} for glycine
without isotopic substitution (HH) displays a much smaller extent than
occurs with the substitution of the deuterium (HD) or tritium (HT)
isotopes. In all three cases HH, HD and HT we can distinguish the
presence of the CCW and CW directions of torsions by examination of the
C1-C2 \emph{BCP} T\selectlanguage{greek}\textsubscript{σ}\selectlanguage{english}(s). The S\textsubscript{a} and
R\textsubscript{a} stress tensor trajectories T\selectlanguage{greek}\textsubscript{σ}\selectlanguage{english}(s) of
the torsional C1-C2 \emph{BCP} , appear to be indistinguishable for the
HD glycine, but not for the HT glycine. The T\selectlanguage{greek}\textsubscript{σ}\selectlanguage{english}(s) of the
non-torsional C-H3/10/D3/T3 \emph{BCPs}occur in response to the
torsional C1-C2 \emph{BCP} , see \textbf{Figure S4} of the
\textbf{Supplementary Materials S4} . The T\selectlanguage{greek}\textsubscript{σ}\selectlanguage{english}(s) of the
C-D3/T3 \emph{BCP} corresponding to the DH and DT are larger in extent
for the HH glycine. The chirality C\selectlanguage{greek}\textsubscript{σ} \selectlanguage{english}determined by the
torsional C1-C2 \emph{BCP} for the formally achiral HH glycine (0.057)
in \textbf{Table S3} of the\textbf{Supplementary Materials S3} is
comparable to the torsional C1-C2\emph{BCP} in lactic acid that can be
seen from inspection of\textbf{Table 1} in some of the current authors
previous work\textsuperscript{46} to be 0.078 and -0.077 for the S and R
stereoisomers respectively.\selectlanguage{english}
\begin{figure}[H]
\begin{center}
\includegraphics[width=0.70\columnwidth]{figures/image17/image17}

\end{center}
\end{figure}\selectlanguage{english}
\begin{figure}[H]
\begin{center}
\includegraphics[width=0.70\columnwidth]{figures/image18/image18}

\end{center}
\end{figure}\selectlanguage{english}
\begin{figure}[H]
\begin{center}
\includegraphics[width=0.70\columnwidth]{figures/image19/image19}

\end{center}
\end{figure}

\textbf{Figure 2} . The stress tensor trajectories T\selectlanguage{greek}\textsubscript{σ}\selectlanguage{english}(s)
of the CW and CCW directions of torsion of the torsional C1-N7\emph{BCP}
bond-path for glycine (HH) (left panel) and HD (middle panel), HT(right
panel) isotopomers of glycine are presented, see the caption of
\textbf{Figure 1} for further details.\selectlanguage{english}
\begin{figure}[H]
\begin{center}
\includegraphics[width=0.70\columnwidth]{figures/image20/image20}

\end{center}
\end{figure}\selectlanguage{english}
\begin{figure}[H]
\begin{center}
\includegraphics[width=0.70\columnwidth]{figures/image21/image21}

\end{center}
\end{figure}\selectlanguage{english}
\begin{figure}[H]
\begin{center}
\includegraphics[width=0.70\columnwidth]{figures/image22/image22}

\end{center}
\end{figure}

\textbf{(a)}\selectlanguage{english}
\begin{figure}[H]
\begin{center}
\includegraphics[width=0.70\columnwidth]{figures/image23/image23}

\end{center}
\end{figure}\selectlanguage{english}
\begin{figure}[H]
\begin{center}
\includegraphics[width=0.70\columnwidth]{figures/image24/image24}

\end{center}
\end{figure}

\textbf{(b)}

\textbf{Figure 3.} The stress tensor trajectories
T\selectlanguage{greek}\textsubscript{σ}\selectlanguage{english}(\emph{s} ) of the CW (-180.0\selectlanguage{ngerman}° \selectlanguage{english}[?] \selectlanguage{greek}θ \selectlanguage{english}[?] \selectlanguage{english}0.0\selectlanguage{ngerman}°) and CCW (0°
\selectlanguage{english}[?] \selectlanguage{greek}θ \selectlanguage{english}[?] \selectlanguage{english}180.0\selectlanguage{ngerman}°) rotations of the C1-H3 \emph{BCP} bond-path and
C1-H10\emph{BCP} bond-path of C1-N7 \emph{BCP} torsional bonds for
glycine (left panel), the corresponding plots for the C1-D3/D10
\emph{BCP}(middle panel) and C1-T3/T10 \emph{BCP} (right panel) are
presented in sub-figure \textbf{(a)} . The T\selectlanguage{greek}\textsubscript{σ}\selectlanguage{english}(\emph{s} )
of the non-isotopomer C-H3/10 \emph{BCP} s are presented in
sub-figure\textbf{(b)} , also see the caption of \textbf{Figure 1} for
further details.

\textbf{Table 2(a).} The maximum projections T\selectlanguage{greek}\textsubscript{σ}\selectlanguage{english}(\emph{s}
)\textsubscript{max} =
\{\selectlanguage{greek}\textbf{(e\textsubscript{1σ}[?]dr)\textsubscript{max} -}
bond-twist,\selectlanguage{greek}\textbf{(e\textsubscript{2σ}[?]dr)\textsubscript{max} -}
bond-flexing,\selectlanguage{greek}\textbf{(\emph{e}\textsubscript{3σ}.dr)\textsubscript{max}}\selectlanguage{english}
\textbf{-}bond-axiality\} values for the C1-N7 \emph{BCP} , C1-H3/D3/T3
\emph{BCP} , C1-H10/D10/T10 \emph{BCP} , C2-O5 \emph{BCP} and O5-H6
\emph{BCP}bond-paths of the CW and CCW torsions of the C1-N7 \emph{BCP}
bond-path of the isotopomers of glycine, all entries are multiplied by
10\textsuperscript{3}.

T\selectlanguage{greek}\textsubscript{σ}\selectlanguage{english}(\emph{s})\textsubscript{max}\selectlanguage{english}
\begin{longtable}[]{@{}llllllllll@{}}
\toprule
\textbf{S\textsubscript{a} R\textsubscript{a}} &
\textbf{S\textsubscript{a} R\textsubscript{a}} &
\textbf{S\textsubscript{a} R\textsubscript{a}} &
\textbf{S\textsubscript{a} R\textsubscript{a}} &
\textbf{S\textsubscript{a} R\textsubscript{a}} &
\textbf{S\textsubscript{a} R\textsubscript{a}} &
\textbf{S\textsubscript{a} R\textsubscript{a}} &
\textbf{S\textsubscript{a} R\textsubscript{a}} &
\textbf{S\textsubscript{a} R\textsubscript{a}} &
\textbf{S\textsubscript{a} R\textsubscript{a}}\tabularnewline
Isotopomer & \textbf{CW} & \textbf{CW} & \textbf{CCW} & \textbf{CCW} &
\textbf{CW} & \textbf{CW} & \textbf{CW} & \textbf{CW} &
\textbf{CCW}\tabularnewline
\emph{HD} & \emph{HD} & \emph{HD} & \emph{HD} & \emph{HD} & \emph{HD} &
\emph{HD} & & &\tabularnewline
C1-N7 & \{1.25969, 6.20430, 1.17453\} & \{1.25969, 6.20430, 1.17453\} &
\{1.46775, 6.66070, 0.98733\} & \{1.46775, 6.66070, 0.98733\} &
\{1.25965, 6.20425, 1.17653\} & \{1.25965, 6.20425, 1.17653\} &
\{1.25965, 6.20425, 1.17653\} & \{1.25965, 6.20425, 1.17653\} &
\{1.46784, 6.66056, 0.98735\}\tabularnewline
C1-H3 & \{---, ---, ---\} & \{---, ---, ---\} & \{---, ---, ---\} &
\{---, ---, ---\} & \{5.36658, 4.61228, 1.11240\} & \{5.36658, 4.61228,
1.11240\} & \{5.36658, 4.61228, 1.11240\} & \{5.36658, 4.61228,
1.11240\} & \{6.31493, 4.48255, 1.58443\}\tabularnewline
C1-D3 & \{5.36654, 4.61234, 1.11207\} & \{5.36654, 4.61234, 1.11207\} &
\{6.31495, 4.49247, 1.58430\} & \{6.31495, 4.49247, 1.58430\} & \{---,
---, ---\} & \{---, ---, ---\} & \{---, ---, ---\} & \{---, ---, ---\} &
\{---, ---, ---\}\tabularnewline
C1-H10 & \{5.98267, 4.21167, 1.47115\} & \{5.98267, 4.21167, 1.47115\} &
\{5.65679, 5.06483, 1.31864\} & \{5.65679, 5.06483, 1.31864\} & \{---,
---, ---\} & \{---, ---, ---\} & \{---, ---, ---\} & \{---, ---, ---\} &
\{---,---, ---\}\tabularnewline
C1-D10 & \{---, ---, ---\} & \{---, ---, ---\} & \{---, ---, ---\} &
\{---, ---, ---\} & \{5.98258, 4.21165, 1.47086\} & \{5.98258, 4.21165,
1.47086\} & \{5.98258, 4.21165, 1.47086\} & \{5.98258, 4.21165,
1.47086\} & \{5.65675, 5.06488, 1.31863\}\tabularnewline
C2-O5 & \{2.82360, 3.94348, 2.87514\} & \{2.82360, 3.94348, 2.87514\} &
\{3.32765, 4.37802, 3.93280\} & \{3.32765, 4.37802, 3.93280\} &
\{2.82333, 3.94361, 2.87495\} & \{2.82333, 3.94361, 2.87495\} &
\{2.82333, 3.94361, 2.87495\} & \{2.82333, 3.94361, 2.87495\} &
\{3.32759, 4.37821, 3.93148\}\tabularnewline
O5-H6 & \{25.61721, 1.11027,6.38973\} & \{25.61721, 1.11027,6.38973\} &
\{28.60879, 1.67954,8.25715\} & \{28.60879, 1.67954,8.25715\} &
\{25.61738, 1.10925,6.38971\} & \{25.61738, 1.10925,6.38971\} &
\{25.61738, 1.10925,6.38971\} & \{25.61738, 1.10925,6.38971\} &
\{28.60883, 1.67965,8.25713\}\tabularnewline
\emph{HT} & \emph{HT} & \emph{HT} & \emph{HT} & \emph{HT} & \emph{HT} &
\emph{HT} & \emph{HT} & &\tabularnewline
C1-N7 & \{1.34308, 6.22003, 1.20499\} & \{1.34308, 6.22003, 1.20499\} &
\{1.31574, 6.81512, 0.97125\} & \{1.31574, 6.81512, 0.97125\} &
\{1.38459, 6.17378, 1.12404\} & \{1.38459, 6.17378, 1.12404\} &
\{1.38459, 6.17378, 1.12404\} & \{1.38459, 6.17378, 1.12404\} &
\{1.26306, 6.86274, 1.08107\}\tabularnewline
C1-H3 & \{---, ---, ---\} & \{---, ---, ---\} & \{---, ---, ---\} &
\{---, ---, ---\} & \{5.31281, 4.75163, 1.07927\} & \{5.31281, 4.75163,
1.07927\} & \{5.31281, 4.75163, 1.07927\} & \{5.31281, 4.75163,
1.07927\} & \{6.42394, 4.83984, 1.59242\}\tabularnewline
C1-T3 & \{5.34733, 4.68833, 1.17787\} & \{5.34733, 4.68833, 1.17787\} &
\{6.47606, 4.81406, 1.47222\} & \{6.47606, 4.81406, 1.47222\} & \{---,
---, ---\} & \{---, ---, ---\} & \{---, ---, ---\} & \{---, ---, ---\} &
\{---, ---, ---\}\tabularnewline
C1-H10 & \{5.86356, 4.46846, 1.42940\} & \{5.86356, 4.46846, 1.42940\} &
\{5.87796, 5.10046, 1.19824\} & \{5.87796, 5.10046, 1.19824\} & \{---,
---, ---\} & \{---, ---, ---\} & \{---, ---, ---\} & \{---, ---, ---\} &
\{---, ---, ---\}\tabularnewline
C1-T10 & \{---, ---, ---\} & \{---, ---, ---\} & \{---, ---, ---\} &
\{---, ---, ---\} & \{5.91646, 4.45681, 1.31813\} & \{5.91646, 4.45681,
1.31813\} & \{5.91646, 4.45681, 1.31813\} & \{5.91646, 4.45681,
1.31813\} & \{5.91642, 5.04547, 1.30523\}\tabularnewline
C2-O5 & \{2.12201, 4.47510, 2.14513\} & \{2.12201, 4.47510, 2.14513\} &
\{2.48854, 4.85582, 2.75258\} & \{2.48854, 4.85582, 2.75258\} &
\{2.09898, 4.54420, 2.19412\} & \{2.09898, 4.54420, 2.19412\} &
\{2.09898, 4.54420, 2.19412\} & \{2.09898, 4.54420, 2.19412\} &
\{2.51075, 4.78969, 2.78793\}\tabularnewline
O5-H6 & \{25.42079, 0.86864,4.96079\} & \{25.42079, 0.86864,4.96079\} &
\{27.74975, 1.22755,6.00838\} & \{27.74975, 1.22755,6.00838\} &
\{25.67682, 0.84830,5.17380\} & \{25.67682, 0.84830,5.17380\} &
\{25.67682, 0.84830,5.17380\} & \{25.67682, 0.84830,5.17380\} &
\{27.51096, 1.23414,6.17940\}\tabularnewline
\emph{HH} & \emph{HH} & CW & CW & CW & CW & CCW & CCW & CCW &
CCW\tabularnewline
C1-N7 & \{3.26019, 1.60696, 0.54036\} & \{3.26019, 1.60696, 0.54036\} &
\{3.26019, 1.60696, 0.54036\} & \{3.44982, 1.27642, 0.71997\} &
\{3.44982, 1.27642, 0.71997\} & \{3.44982, 1.27642, 0.71997\} &
\{3.44982, 1.27642, 0.71997\} & \{3.44982, 1.27642, 0.71997\} &
\{3.44982, 1.27642, 0.71997\}\tabularnewline
C1-H3 & \{3.33726, 3.75752, 0.35676\} & \{3.33726, 3.75752, 0.35676\} &
\{3.33726, 3.75752, 0.35676\} & \{3.79503, 4.68194, 0.71777\} &
\{3.79503, 4.68194, 0.71777\} & \{3.79503, 4.68194, 0.71777\} &
\{3.79503, 4.68194, 0.71777\} & \{3.79503, 4.68194, 0.71777\} &
\{3.79503, 4.68194, 0.71777\}\tabularnewline
C1-H10 & \{3.90399, 4.38773, 0.55697\} & \{3.90399, 4.38773, 0.55697\} &
\{3.90399, 4.38773, 0.55697\} & \{4.47024, 4.33847, 0.39951\} &
\{4.47024, 4.33847, 0.39951\} & \{4.47024, 4.33847, 0.39951\} &
\{4.47024, 4.33847, 0.39951\} & \{4.47024, 4.33847, 0.39951\} &
\{4.47024, 4.33847, 0.39951\}\tabularnewline
C2-O5 & \{2.82335, 3.94348, 2.87501\} & \{2.82335, 3.94348, 2.87501\} &
\{2.82335, 3.94348, 2.87501\} & \{3.32762, 4.37806, 3.93266\} &
\{3.32762, 4.37806, 3.93266\} & \{3.32762, 4.37806, 3.93266\} &
\{3.32762, 4.37806, 3.93266\} & \{3.32762, 4.37806, 3.93266\} &
\{3.32762, 4.37806, 3.93266\}\tabularnewline
O5-H6 & \{25.61750, 1.10918, 6.38972\} & \{25.61750, 1.10918, 6.38972\}
& \{25.61750, 1.10918, 6.38972\} & \{28.60857, 1.67940, 8.25731\} &
\{28.60857, 1.67940, 8.25731\} & \{28.60857, 1.67940, 8.25731\} &
\{28.60857, 1.67940, 8.25731\} & \{28.60857, 1.67940, 8.25731\} &
\{28.60857, 1.67940, 8.25731\}\tabularnewline
\bottomrule
\end{longtable}

\textbf{Table 2(b).} The values of the chirality C\selectlanguage{greek}\textsubscript{σ} \selectlanguage{english}=
{[}\selectlanguage{greek}\textbf{(e\textsubscript{1σ}[?]dr)\textsubscript{max}}\selectlanguage{english}
{]}\textsubscript{\textbf{CCW}}-
{[}\selectlanguage{greek}\textbf{(e\textsubscript{1σ}[?]dr)\textsubscript{max}}\selectlanguage{english}
{]}\textsubscript{\textbf{CW}} , bond-flexing F\selectlanguage{greek}\textsubscript{σ} \selectlanguage{english}=
{[}\selectlanguage{greek}\textbf{(e\textsubscript{2σ}[?]dr)\textsubscript{max}}\selectlanguage{english}
{]}\textsubscript{\textbf{CCW}}-
{[}\selectlanguage{greek}\textbf{(e\textsubscript{2σ}[?]dr)\textsubscript{max}}\selectlanguage{english}
{]}\textsubscript{\textbf{CW}}and bond-axiality A\selectlanguage{greek}\textsubscript{σ} \selectlanguage{english}=
{[}\selectlanguage{greek}\textbf{(e\textsubscript{3σ}[?]dr)\textsubscript{max}}\selectlanguage{english}
{]}\textsubscript{\textbf{CCW}}-
{[}\selectlanguage{greek}\textbf{(e\textsubscript{3σ}[?]dr)\textsubscript{max}}\selectlanguage{english}
{]}\textsubscript{\textbf{CW}}of the torsional C1-N7 \emph{BCP} for the
isotopomers of glycine are presented, all entries are multiplied by
10\textsuperscript{3}. The stereoisomeric excess X\selectlanguage{greek}\textsubscript{σ} \selectlanguage{english}is
defined as the ratio of the magnitude of the C\selectlanguage{greek}\textsubscript{σ} \selectlanguage{english}values
of the S\textsubscript{a} and R\textsubscript{a} stereoisomers of the
torsional C1-N7 \emph{BCP} .

\{C\selectlanguage{greek}\textsubscript{σ}, \selectlanguage{english}F\selectlanguage{greek}\textsubscript{σ}, \selectlanguage{english}A\selectlanguage{greek}\textsubscript{σ}\selectlanguage{english}\}\selectlanguage{english}
\begin{longtable}[]{@{}llllllll@{}}
\toprule
Isotopomer & \textbf{S\textsubscript{a}} & \textbf{R\textsubscript{a}} &
\textbf{R\textsubscript{a}} & \textbf{R\textsubscript{a}} &
X\selectlanguage{greek}\textsubscript{σ} & X\selectlanguage{greek}\textsubscript{σ} &
X\selectlanguage{greek}\textsubscript{σ}\selectlanguage{english}\tabularnewline
\emph{HD} & \{0.20806{[}\selectlanguage{greek}\selectlanguage{english}\textbf{S\textsubscript{σ}}{]},
0.45640{[}\selectlanguage{greek}\selectlanguage{english}\textbf{S\textsubscript{σ}}{]},
-0.18720{[}\selectlanguage{greek}\selectlanguage{english}\textbf{R\textsubscript{σ}}{]}\} &
\{0.20806{[}\selectlanguage{greek}\selectlanguage{english}\textbf{S\textsubscript{σ}}{]},
0.45640{[}\selectlanguage{greek}\selectlanguage{english}\textbf{S\textsubscript{σ}}{]},
-0.18720{[}\selectlanguage{greek}\selectlanguage{english}\textbf{R\textsubscript{σ}}{]}\} &
\{0.20819{[}\selectlanguage{greek}\selectlanguage{english}\textbf{S\textsubscript{σ}}{]}\textbf{,}
0.45631{[}\selectlanguage{greek}\selectlanguage{english}\textbf{S\textsubscript{σ}}{]},
-0.18918{[}\selectlanguage{greek}\selectlanguage{english}\textbf{R\textsubscript{σ}}{]}\} &
\{0.20819{[}\selectlanguage{greek}\selectlanguage{english}\textbf{S\textsubscript{σ}}{]}\textbf{,}
0.45631{[}\selectlanguage{greek}\selectlanguage{english}\textbf{S\textsubscript{σ}}{]},
-0.18918{[}\selectlanguage{greek}\selectlanguage{english}\textbf{R\textsubscript{σ}}{]}\} &
\{0.20819{[}\selectlanguage{greek}\selectlanguage{english}\textbf{S\textsubscript{σ}}{]}\textbf{,}
0.45631{[}\selectlanguage{greek}\selectlanguage{english}\textbf{S\textsubscript{σ}}{]},
-0.18918{[}\selectlanguage{greek}\selectlanguage{english}\textbf{R\textsubscript{σ}}{]}\} & 0.99938 &
0.99938\tabularnewline
\emph{HT} & \{-0.02734{[}\selectlanguage{greek}\selectlanguage{english}\textbf{R\textsubscript{σ}}{]}\textbf{,}
0.59509{[}\selectlanguage{greek}\selectlanguage{english}\textbf{S\textsubscript{σ}}{]},
-0.23374{[}\selectlanguage{greek}\selectlanguage{english}\textbf{R\textsubscript{σ}}{]}\} &
\{-0.02734{[}\selectlanguage{greek}\selectlanguage{english}\textbf{R\textsubscript{σ}}{]}\textbf{,}
0.59509{[}\selectlanguage{greek}\selectlanguage{english}\textbf{S\textsubscript{σ}}{]},
-0.23374{[}\selectlanguage{greek}\selectlanguage{english}\textbf{R\textsubscript{σ}}{]}\} &
\{-0.02734{[}\selectlanguage{greek}\selectlanguage{english}\textbf{R\textsubscript{σ}}{]}\textbf{,}
0.59509{[}\selectlanguage{greek}\selectlanguage{english}\textbf{S\textsubscript{σ}}{]},
-0.23374{[}\selectlanguage{greek}\selectlanguage{english}\textbf{R\textsubscript{σ}}{]}\} &
\{-0.12153{[}\selectlanguage{greek}\selectlanguage{english}\textbf{R\textsubscript{σ}}{]}\textbf{,}
0.68896{[}\selectlanguage{greek}\selectlanguage{english}\textbf{S\textsubscript{σ}}{]},
-0.04297{[}\selectlanguage{greek}\selectlanguage{english}\textbf{R\textsubscript{σ}}{]}\} &
\{-0.12153{[}\selectlanguage{greek}\selectlanguage{english}\textbf{R\textsubscript{σ}}{]}\textbf{,}
0.68896{[}\selectlanguage{greek}\selectlanguage{english}\textbf{S\textsubscript{σ}}{]},
-0.04297{[}\selectlanguage{greek}\selectlanguage{english}\textbf{R\textsubscript{σ}}{]}\} &
\{-0.12153{[}\selectlanguage{greek}\selectlanguage{english}\textbf{R\textsubscript{σ}}{]}\textbf{,}
0.68896{[}\selectlanguage{greek}\selectlanguage{english}\textbf{S\textsubscript{σ}}{]},
-0.04297{[}\selectlanguage{greek}\selectlanguage{english}\textbf{R\textsubscript{σ}}{]}\} & 0.22497\tabularnewline
& \{C\selectlanguage{greek}\textsubscript{σ}, \selectlanguage{english}F\selectlanguage{greek}\textsubscript{σ}, \selectlanguage{english}A\selectlanguage{greek}\textsubscript{σ}\selectlanguage{english}\} &
\{C\selectlanguage{greek}\textsubscript{σ}, \selectlanguage{english}F\selectlanguage{greek}\textsubscript{σ}, \selectlanguage{english}A\selectlanguage{greek}\textsubscript{σ}\selectlanguage{english}\} &
\{C\selectlanguage{greek}\textsubscript{σ}, \selectlanguage{english}F\selectlanguage{greek}\textsubscript{σ}, \selectlanguage{english}A\selectlanguage{greek}\textsubscript{σ}\selectlanguage{english}\} &
\{C\selectlanguage{greek}\textsubscript{σ}, \selectlanguage{english}F\selectlanguage{greek}\textsubscript{σ}, \selectlanguage{english}A\selectlanguage{greek}\textsubscript{σ}\selectlanguage{english}\} &
\{C\selectlanguage{greek}\textsubscript{σ}, \selectlanguage{english}F\selectlanguage{greek}\textsubscript{σ}, \selectlanguage{english}A\selectlanguage{greek}\textsubscript{σ}\selectlanguage{english}\} &
\{C\selectlanguage{greek}\textsubscript{σ}, \selectlanguage{english}F\selectlanguage{greek}\textsubscript{σ}, \selectlanguage{english}A\selectlanguage{greek}\textsubscript{σ}\selectlanguage{english}\} &
\{C\selectlanguage{greek}\textsubscript{σ}, \selectlanguage{english}F\selectlanguage{greek}\textsubscript{σ},
\selectlanguage{english}A\selectlanguage{greek}\textsubscript{σ}\selectlanguage{english}\}\tabularnewline
\emph{HH} & \{0.18963{[}\selectlanguage{greek}\selectlanguage{english}\textbf{S\textsubscript{σ}}{]}\textbf{,}
-0.33054{[}\selectlanguage{greek}\selectlanguage{english}\textbf{R\textsubscript{σ}}{]},
0.17961{[}\selectlanguage{greek}\selectlanguage{english}\textbf{S\textsubscript{σ}}{]}\} &
\{0.18963{[}\selectlanguage{greek}\selectlanguage{english}\textbf{S\textsubscript{σ}}{]}\textbf{,}
-0.33054{[}\selectlanguage{greek}\selectlanguage{english}\textbf{R\textsubscript{σ}}{]},
0.17961{[}\selectlanguage{greek}\selectlanguage{english}\textbf{S\textsubscript{σ}}{]}\} &
\{0.18963{[}\selectlanguage{greek}\selectlanguage{english}\textbf{S\textsubscript{σ}}{]}\textbf{,}
-0.33054{[}\selectlanguage{greek}\selectlanguage{english}\textbf{R\textsubscript{σ}}{]},
0.17961{[}\selectlanguage{greek}\selectlanguage{english}\textbf{S\textsubscript{σ}}{]}\} &
\{0.18963{[}\selectlanguage{greek}\selectlanguage{english}\textbf{S\textsubscript{σ}}{]}\textbf{,}
-0.33054{[}\selectlanguage{greek}\selectlanguage{english}\textbf{R\textsubscript{σ}}{]},
0.17961{[}\selectlanguage{greek}\selectlanguage{english}\textbf{S\textsubscript{σ}}{]}\} &
\{0.18963{[}\selectlanguage{greek}\selectlanguage{english}\textbf{S\textsubscript{σ}}{]}\textbf{,}
-0.33054{[}\selectlanguage{greek}\selectlanguage{english}\textbf{R\textsubscript{σ}}{]},
0.17961{[}\selectlanguage{greek}\selectlanguage{english}\textbf{S\textsubscript{σ}}{]}\} &
\{0.18963{[}\selectlanguage{greek}\selectlanguage{english}\textbf{S\textsubscript{σ}}{]}\textbf{,}
-0.33054{[}\selectlanguage{greek}\selectlanguage{english}\textbf{R\textsubscript{σ}}{]},
0.17961{[}\selectlanguage{greek}\selectlanguage{english}\textbf{S\textsubscript{σ}}{]}\} &
\{0.18963{[}\selectlanguage{greek}\selectlanguage{english}\textbf{S\textsubscript{σ}}{]}\textbf{,}
-0.33054{[}\selectlanguage{greek}\selectlanguage{english}\textbf{R\textsubscript{σ}}{]},
0.17961{[}\selectlanguage{greek}\selectlanguage{english}\textbf{S\textsubscript{σ}}{]}\}\tabularnewline
\bottomrule
\end{longtable}

We now consider the chirality C\selectlanguage{greek}\textsubscript{σ}, \selectlanguage{english}bond-flexing
F\selectlanguage{greek}\textsubscript{σ} \selectlanguage{english}and bond-axiality A\selectlanguage{greek}\textsubscript{σ} \selectlanguage{english}values of the
dominant torsional C1-N7 \emph{BCP} , see \textbf{Figure 2}
and\textbf{Table 2(b)} . The formally achiral HH glycine comprises a
significant degree of chirality C\selectlanguage{greek}\textsubscript{σ} \selectlanguage{english}(= 0.18963) for the
torsional C1-N7 \emph{BCP} with \selectlanguage{greek}\textbf{S\textsubscript{σ}} \selectlanguage{english}character,
see \textbf{Table 2(a-b)} . The magnitude of C\selectlanguage{greek}\textsubscript{σ}
\selectlanguage{english}increases similarly with the addition of the D isotope for both the
S\textsubscript{a} and R\textsubscript{a} stereoisomers, where the
R\textsubscript{a} stereoisomer possesses the larger value, both
stereoisomers are \selectlanguage{greek}\textbf{S\textsubscript{σ}} \selectlanguage{english}character. The
bond-flexing F\selectlanguage{greek}\textsubscript{σ} \selectlanguage{english}is more affected by the substitution of
the D isotope to HH glycine than either of the chirality
C\selectlanguage{greek}\textsubscript{σ} \selectlanguage{english}or A\selectlanguage{greek}\textsubscript{σ} \selectlanguage{english}of the torsional
C1-N7\emph{BCP} , see \textbf{Table 2(b)} .

The substitution of the T isotope onto the alpha carbon of HH glycine to
replace an H significantly changes C\selectlanguage{greek}\textsubscript{σ},
\selectlanguage{english}F\selectlanguage{greek}\textsubscript{σ} \selectlanguage{english}and A\selectlanguage{greek}\textsubscript{σ} \selectlanguage{english}values. The T isotope changes
the character of the chirality C\selectlanguage{greek}\textsubscript{σ}
\selectlanguage{english}to\selectlanguage{greek}\textbf{R\textsubscript{σ}} \selectlanguage{english}character for both the
S\textsubscript{a}and R\textsubscript{a} stereoisomers and there is a
pronounced difference in the magnitude of C\selectlanguage{greek}\textsubscript{σ}, \selectlanguage{english}that is
significantly lower for the S\textsubscript{a} stereoisomer. The
bond-flexing F\selectlanguage{greek}\textsubscript{σ} \selectlanguage{english}increases in magnitude from HH glycine
through to HD glycine and HT glycine, again the HD glycine values are
similar for the S\textsubscript{a} and R\textsubscript{a} stereoisomers
with a slight preference for the S\textsubscript{a} stereoisomer. In
addition, the bond-flexing F\selectlanguage{greek}\textsubscript{σ} \selectlanguage{english}changes from
\selectlanguage{greek}\textbf{S\textsubscript{σ}}\selectlanguage{english}character, for HH glycine, to
\selectlanguage{greek}\textbf{R\textsubscript{σ}} \selectlanguage{english}character for both the S\textsubscript{a}
and R\textsubscript{a} stereoisomers of HD glycine and HT glycine. The
bond-axiality A\selectlanguage{greek}\textsubscript{σ} \selectlanguage{english}increases in magnitude from HH glycine
through to HD glycine and S\textsubscript{a} stereoisomer of HT glycine,
again the HD glycine values are similar for the S\textsubscript{a} and
R\textsubscript{a}stereoisomers with a slight preference for the
R\textsubscript{a}stereoisomer. The A\selectlanguage{greek}\textsubscript{σ} \selectlanguage{english}value of the
R\textsubscript{a}stereoisomer of HT glycine decreases significantly
below that of HH glycine. The A\selectlanguage{greek}\textsubscript{σ} \selectlanguage{english}value of HH glycine
possesses\selectlanguage{greek}\textbf{S\textsubscript{σ}} \selectlanguage{english}character that changes
to\selectlanguage{greek}\textbf{R\textsubscript{σ}} \selectlanguage{english}character for both the
S\textsubscript{a}and R\textsubscript{a} stereoisomers of HD glycine and
HT glycine. The stereoisomeric excess X\selectlanguage{greek}\textsubscript{σ} \selectlanguage{english}values indicate
a very slight preference for the R\textsubscript{a} stereoisomer that
possesses chirality C\selectlanguage{greek}\textsubscript{σ} \selectlanguage{english}with \selectlanguage{greek}\textbf{S\textsubscript{σ}}
\selectlanguage{english}character for HD glycine and a very strong preference for the
R\textsubscript{a}stereoisomer that possesses chirality
C\selectlanguage{greek}\textsubscript{σ} \selectlanguage{english}with\selectlanguage{greek}\textbf{R\textsubscript{σ}} \selectlanguage{english}character for HD
glycine.

\textbf{Table 2(c).} Values of the bond-twist T\selectlanguage{greek}\textsubscript{σ} \selectlanguage{english}=
{[}\selectlanguage{greek}\textbf{(e\textsubscript{1σ}[?]dr)\textsubscript{max}}\selectlanguage{english}
{]}\textsubscript{\textbf{CCW}}-
{[}\selectlanguage{greek}\textbf{(e\textsubscript{1σ}[?]dr)\textsubscript{max}}\selectlanguage{english}
{]}\textsubscript{\textbf{CW}} , bond-flexing F\selectlanguage{greek}\textsubscript{σ} \selectlanguage{english}and the
bond-axiality A\selectlanguage{greek}\textsubscript{σ}\selectlanguage{english}of the C-H/D/T \emph{BCP} bond-paths
corresponding to the torsional C1-N7 \emph{BCP} bond-path of the
isotopomers of glycine are presented, see the caption of \textbf{Table
2(b)} for further details.\selectlanguage{english}
\begin{longtable}[]{@{}lll@{}}
\toprule
Isotopomer & \{T\selectlanguage{greek}\textsubscript{σ}, \selectlanguage{english}F\selectlanguage{greek}\textsubscript{σ},
\selectlanguage{english}A\selectlanguage{greek}\textsubscript{σ}\selectlanguage{english}\} & \{T\selectlanguage{greek}\textsubscript{σ}, \selectlanguage{english}F\selectlanguage{greek}\textsubscript{σ},
\selectlanguage{english}A\selectlanguage{greek}\textsubscript{σ}\selectlanguage{english}\}\tabularnewline
\midrule
\endhead
HD & \textbf{S\textsubscript{a}} &
\textbf{R\textsubscript{a}}\tabularnewline
C1-H3 & \{---, ---, ---\} & \{0.94835, -0.11973,
0.47203\}\tabularnewline
C1-D3 & \{0.94841, -0.11987, 0.47223\} & \{---, ---,
---\}\tabularnewline
C1-H10 & \{-0.32583, 0.85323, -0.15223\} & \{---, ---,
---\}\tabularnewline
C1-D10 & \{---, ---, ---\} & \{-0.32588, 0.85326,
-0.15251\}\tabularnewline
\emph{HT} & &\tabularnewline
C1-H3 & \{---, ---, ---\} & \{---, ---, ---\}\tabularnewline
C1-T3 & \{1.12873, 0.12573, 0.29435\} & \{---, ---, ---\}\tabularnewline
C1-H10 & \{0.01440, 0.63200, -0.23116\} & \{---, ---,
---\}\tabularnewline
C1-T10 & \{---, ---, ---\} & \{-0.00004, 0.58866,
-0.01290\}\tabularnewline
\emph{HH} & \{T\selectlanguage{greek}\textsubscript{σ}, \selectlanguage{english}F\selectlanguage{greek}\textsubscript{σ},
\selectlanguage{english}A\selectlanguage{greek}\textsubscript{σ}\selectlanguage{english}\} & \{T\selectlanguage{greek}\textsubscript{σ}, \selectlanguage{english}F\selectlanguage{greek}\textsubscript{σ},
\selectlanguage{english}A\selectlanguage{greek}\textsubscript{σ}\selectlanguage{english}\}\tabularnewline
C1-H3 & \{0.45777, 0.92442, 0.36101\} & \{0.45777, 0.92442,
0.36101\}\tabularnewline
C1-H10 & \{0.56625, -0.04926, -0.15746\} & \{0.56625, -0.04926,
-0.15746\}\tabularnewline
\bottomrule
\end{longtable}

\textbf{Table 2(d).} Values of the bond-twist T\selectlanguage{greek}\textsubscript{σ},
\selectlanguage{english}bond-flexing F\selectlanguage{greek}\textsubscript{σ} \selectlanguage{english}and the bond-axiality
A\selectlanguage{greek}\textsubscript{σ}\selectlanguage{english}of the C2-O5 \emph{BCP} and O5-H6 \emph{BCP}
bond-paths corresponding to the torsional C1-N7 \emph{BCP} bond-path of
the isotopomers of glycine are presented, see the caption of
\textbf{Table 2(b)} for further details.\selectlanguage{english}
\begin{longtable}[]{@{}llll@{}}
\toprule
Isotopomer & \{T\selectlanguage{greek}\textsubscript{σ}, \selectlanguage{english}F\selectlanguage{greek}\textsubscript{σ},
\selectlanguage{english}A\selectlanguage{greek}\textsubscript{σ}\selectlanguage{english}\} & \{T\selectlanguage{greek}\textsubscript{σ}, \selectlanguage{english}F\selectlanguage{greek}\textsubscript{σ},
\selectlanguage{english}A\selectlanguage{greek}\textsubscript{σ}\selectlanguage{english}\} & \{T\selectlanguage{greek}\textsubscript{σ}, \selectlanguage{english}F\selectlanguage{greek}\textsubscript{σ},
\selectlanguage{english}A\selectlanguage{greek}\textsubscript{σ}\selectlanguage{english}\}\tabularnewline
\midrule
\endhead
HD & \textbf{S\textsubscript{a}} & \textbf{R\textsubscript{a}} &
\textbf{R\textsubscript{a}}\tabularnewline
C2-O5 & \{0.50405, 0.43454, 1.05766\} & \{0.50426, 0.43460, 1.05653\} &
\{0.50426, 0.43460, 1.05653\}\tabularnewline
O5-H6 & \{2.99158, 0.56927, 1.86742\} & \{2.99145, 0.57040, 1.86742\} &
\{2.99145, 0.57040, 1.86742\}\tabularnewline
\emph{HT} & & &\tabularnewline
C2-O5 & \{0.36653, 0.38072, 0.60745\} & \{0.41177, 0.24549, 0.59381\} &
\{0.41177, 0.24549, 0.59381\}\tabularnewline
O5-H6 & \{2.32896, 0.35891, 1.04759\} & \{1.83414, 0.38584, 1.00560\} &
\{1.83414, 0.38584, 1.00560\}\tabularnewline
\emph{HH} & \{T\selectlanguage{greek}\textsubscript{σ}, \selectlanguage{english}F\selectlanguage{greek}\textsubscript{σ},
\selectlanguage{english}A\selectlanguage{greek}\textsubscript{σ}\selectlanguage{english}\} & \{T\selectlanguage{greek}\textsubscript{σ}, \selectlanguage{english}F\selectlanguage{greek}\textsubscript{σ},
\selectlanguage{english}A\selectlanguage{greek}\textsubscript{σ}\selectlanguage{english}\} &\tabularnewline
C2-O5 & \{0.50427, 0.43458, 1.05765\} & \{0.50427, 0.43458, 1.05765\} &
\{0.50427, 0.43458, 1.05765\}\tabularnewline
O5-H6 & \{2.99107, 0.57022, 1.86759\} & \{2.99107, 0.57022, 1.86759\} &
\{2.99107, 0.57022, 1.86759\}\tabularnewline
\bottomrule
\end{longtable}

Consideration of the non-torsional C1-H/D/T \emph{BCPs} is presented
in\textbf{Figure 3} , \textbf{Table 2(c)} and \textbf{Table 2(d)} . For
HD glycine the values of T\selectlanguage{greek}\textsubscript{σ}, \selectlanguage{english}F\selectlanguage{greek}\textsubscript{σ} \selectlanguage{english}and
A\selectlanguage{greek}\textsubscript{σ} \selectlanguage{english}are all slightly larger for C1-D3 \emph{BCP} (the
R\textsubscript{a} stereoisomer) than for the corresponding
T\selectlanguage{greek}\textsubscript{σ}, \selectlanguage{english}F\selectlanguage{greek}\textsubscript{σ} \selectlanguage{english}and A\selectlanguage{greek}\textsubscript{σ} \selectlanguage{english}values of
C1-H3 \emph{BCP} (the S\textsubscript{a} stereoisomer), see\textbf{Table
2(c)} . The same correspondence is found for the C1-D10\emph{BCP.} This
does not hold for the HT glycine where the opposite effect is found for
the C1-T10 \emph{BCP} , where all three of the T\selectlanguage{greek}\textsubscript{σ},
\selectlanguage{english}F\selectlanguage{greek}\textsubscript{σ} \selectlanguage{english}and A\selectlanguage{greek}\textsubscript{σ} \selectlanguage{english}values are smaller for the
C1-T10 \emph{BCP} compared with the C1-H10 \emph{BCP} . A mixed effect
is found for the dominance of the T\selectlanguage{greek}\textsubscript{σ}, \selectlanguage{english}F\selectlanguage{greek}\textsubscript{σ}
\selectlanguage{english}and A\selectlanguage{greek}\textsubscript{σ} \selectlanguage{english}values of the C1-T3 \emph{BCP}compared with the
C1-H3 \emph{BCP} . Particularly high values of the F\selectlanguage{greek}\textsubscript{σ}
\selectlanguage{english}and A\selectlanguage{greek}\textsubscript{σ} \selectlanguage{english}are observed for the O5-H6\emph{BCP} and the
C2-O5 \emph{BCP} that reduce significantly with the addition of the T
isotope to X3 and X10 sites. Despite the remotely positioned location of
the C2-O5 \emph{BCP} and O5-H6 \emph{BCP} from the site of the D and T
substitutions, the effect of the T isotope in particular is apparent
where a significant reduction of the T\selectlanguage{greek}\textsubscript{σ},
\selectlanguage{english}F\selectlanguage{greek}\textsubscript{σ} \selectlanguage{english}and A\selectlanguage{greek}\textsubscript{σ} \selectlanguage{english}values of both the C2-O5
\emph{BCP} and O5-H6 \emph{BCP} compared with D and T, see \textbf{Table
2(d)} . These observations are relevant for the interpretation of the
vibrational mode coupling, which affects both IR and CD spectra. This is
because the \emph{high} values of F\selectlanguage{greek}\textsubscript{σ} \selectlanguage{english}and
A\selectlanguage{greek}\textsubscript{σ} \selectlanguage{english}of both the C2-O5 \emph{BCP}and O5-H6 \emph{BCP} that
are consistent with the C2-O5-H6 undergoing a bending vibration which is
coupled to the methylene group wagging which is thus expected to be
preserved upon deuteration at C1. The\emph{lowering} of the
corresponding values of F\selectlanguage{greek}\textsubscript{σ} \selectlanguage{english}and A\selectlanguage{greek}\textsubscript{σ} \selectlanguage{english}for
the T isotope indicates that the C2-O5-H6 bending vibration is uncoupled
from that of C1-HT wagging.

\textbf{5. Conclusions}

Using Next generation QTAIM we discovered
\selectlanguage{greek}\textbf{S\textsubscript{σ}}\selectlanguage{english}character chirality C\selectlanguage{greek}\textsubscript{σ} \selectlanguage{english}for
the dominant torsional C1-N7\emph{BCP} in HH (ordinary) i.e. formally
achiral glycine. The associated bond-flexing F\selectlanguage{greek}\textsubscript{σ} \selectlanguage{english}and
bond-axiality A\selectlanguage{greek}\textsubscript{σ} \selectlanguage{english}possessed \selectlanguage{greek}\textbf{R\textsubscript{σ}}
\selectlanguage{english}and\selectlanguage{greek}\textbf{S\textsubscript{σ}} \selectlanguage{english}character respectively. The introduction
of the D and T isotopes caused a reversal of
the\selectlanguage{greek}\textbf{R\textsubscript{σ}} \selectlanguage{english}and \selectlanguage{greek}\textbf{S\textsubscript{σ}} \selectlanguage{english}character
torsional C1-N7 \emph{BCP} of the bond-flexing F\selectlanguage{greek}\textsubscript{σ} \selectlanguage{english}and
bond-axiality A\selectlanguage{greek}\textsubscript{σ}. \selectlanguage{english}The presence of
the\selectlanguage{greek}\textbf{S\textsubscript{σ}} \selectlanguage{english}character chirality C\selectlanguage{greek}\textsubscript{σ}
\selectlanguage{english}found for ordinary HH glycine was preserved after the addition of the D
isotope but after replacement of the D isotope with the T isotope the
chirality C\selectlanguage{greek}\textsubscript{σ} \selectlanguage{english}reversed to
\selectlanguage{greek}\textbf{R\textsubscript{σ}}\selectlanguage{english}character. This reversal of the chirality
C\selectlanguage{greek}\textsubscript{σ}, \selectlanguage{english}depending on the presence of a D or T isotope on the
alpha carbon adds to the debate as to the nature of the extraterrestrial
origins of chirality in simple amino acids. This is since either D or T
isotopes of hydrogen may be present, albeit at rather low
concentrations, in these hostile extraterrestrial environments.

We also considered the effects of the addition of the D and T isotopes
on the bond-twist T\selectlanguage{greek}\textsubscript{σ}, \selectlanguage{english}bond-flexing F\selectlanguage{greek}\textsubscript{σ}\selectlanguage{english}and
the bond-axiality A\selectlanguage{greek}\textsubscript{σ} \selectlanguage{english}of the non-torsional
C-H/D/T\emph{BCP} s.

This theoretical analysis represents a new challenge for the eventual
observation of glycine chiral properties. Interestingly, for vibrational
spectroscopies the ``classic'' nuclear isotopic effects can be also
exploited to identify any new weak signals not corresponding to the
energy ranges of the main HH species.

As an example, the effect of the addition of the T isotope to the X3 and
X10 sites on lowering the F\selectlanguage{greek}\textsubscript{σ} \selectlanguage{english}and
A\selectlanguage{greek}\textsubscript{σ}\selectlanguage{english}values for the O5-H6 \emph{BCP} and C2-O5 \emph{BCP}
are expected to also affect the C2-O5-H6 group undergoing a bending
vibration, which is strongly coupled to the methylene group wagging for
HH species, but is expected to be uncoupled for HT. Our analysis
therefore, can be used for the interpretation of infrared (IR) spectra
to provide explanations of classical mass-dependent isotopic shifts as
well as modifications in mode coupling and intensity changes.

The feasibility however, of such studies is still very limited, not only
due to expected very weak chiroptical signals but even creation of alpha
carbon monosubstitued D/T glycine in suitable amounts. As a result,
theoretical analysis with NG-QTAIM at present is a unique highly
sensitive method for the detection of isotopic chirality in glycine, an
amino acid that is present in meteoritic organic compounds.

Furthermore this analysis demonstrates the possibility of directly
relating the \selectlanguage{greek}\textbf{R\textsubscript{σ}} /\selectlanguage{english}\selectlanguage{greek}\textbf{S\textsubscript{σ}}
\selectlanguage{english}chirality to the specific D/T isotopic substitution for a molecule in
natural conditions, without the need to introduce external electric
fields or perform challenging and difficult to interpret spectroscopic
experiments. In future, experiments such as those undertaken by
Beaulieu\emph{et al.} on neutral molecules\textsuperscript{28} could be
undertaken to detect coherent helical motion of bound electrons of
formally achiral glycine and therefore assign\selectlanguage{greek}\textbf{R\textsubscript{σ}}
/\selectlanguage{english}\selectlanguage{greek}\textbf{S\textsubscript{σ}} \selectlanguage{english}chirality, possibly including the D isotope
of glycine.

\textbf{Funding:} This research was funded by the National Natural
Science Foundation of China grant number: 21673071. The One Hundred
Talents Foundation of Hunan Province is also gratefully acknowledged for
their support of S.J. and S.R.K.

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