Chiral and Steric Effects in Ethane: A Next Generation QTAIM Interpretation

Abstract

We introduce a development of next generation quantum theory of atoms in molecules (NG-QTAIM) for an investigation of the chirality of ethane and discover a $Q_{\sigma }$ isomer in addition to $S_{\sigma }$ and $R_{\sigma }$ stereoisomers in the stress tensor trajectory $U_{\sigma }$-space. The $Q_{\sigma }$ isomer is defined to be a 'null-isomer' since the value of the chirality-helicity function $\approx 0$. The presence of chiral contributions suggests that steric effects, rather than hyper-conjugation, explain the staggered geometry of ethane. The steric effects, within the NG-QTAIM interpretation, are reduced by a factor of two using an applied electric-field directed down a C-H bond.