(d)
Figure 1. The variation of the relative energy ∆E of the
torsional C1-C2 BCP with the CW (-180.0º ≤ θ ≤ 0.0º) and CCW
(0.0º ≤ θ ≤ 180.0º) directions of torsion for (left panel), the
corresponding variations of the bond-path lengths (BPL) C1-C2 BCP(middle panel) and the ellipticity ε (right panel) of glycine is
presented in Figure 1(a) . The plots for the HD and HT
isotopomers and Sa and Ra stereoisomers
for the CW and CCW directions of the torsional C1-C2 BCP of the
variation of the relative energy ∆E (left panel), the variations
of the BPL (middle panel) and ellipticity ε (right panel) are presented
in Figure 1(b) , also see the Scheme 1 for further
details. The corresponding plots for the torsional C1-N7 BCP are
presented in Figure 1(c) and 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 Table 1(a-b) .
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-BCP , BCP -H3). Note the BPL
< GBL due to the positions of the non-nuclear attractor (NNA)
and geometric centre not coinciding for the hydrogen atom.