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 BCP used to construct the chirality Cσ,
bond-twist Tσ, bond-flexing Fσ and
bond-axiality Aσ is presented in Figures 2-3and Table 2(a-b) and Table 3(a-b) . The geometries of
the torsional scans are provided in the Supplementary Materials
S2 .
For the torsional C1-C2 BCP the presence of non-overlapping
Tσ(s) for the CCW and CW torsions demonstrates the
uniqueness of the Tσ(s) given the highly symmetrical
positioning of the C1-C2 BCP along the containing bond-path, seeScheme 1 and Figures S3 of the Supplementary
Materials S3 . The stress tensor trajectories Tσ(s) of
the torsional C1-C2 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 BCP Tσ(s).
The Sa and Ra stress tensor trajectories
Tσ(s) of the torsional C1-C2 BCP , appear to be
indistinguishable for the HD glycine, but not for the HT glycine. The
Tσ(s) of the non-torsional C-H3/10/D3/T3 BCPsoccur in response to the torsional C1-C2 BCP , see Figure
S4 of the Supplementary Materials S4 . The
Tσ(s) of the C-D3/T3 BCP corresponding to the DH
and DT are larger in extent for the HH glycine. The chirality
Cσ determined by the torsional C1-C2 BCP for the
formally achiral HH glycine (0.057) in Table S3 of theSupplementary Materials S3 is comparable to the torsional C1-C2BCP in lactic acid that can be seen from inspection ofTable 1 in some of the current authors previous
work46 to be 0.078 and -0.077 for the S and R
stereoisomers respectively.