Knowledge Bank

A mechanism is proposed for the production of chiral molecules through the cooperative action of polarized light and vibronic interaction. It requires a doubly-degenerate electronic state of an achiral molecule be splitted by a non-degenerate vibration of pseudoscalar symmetry in a Jahn-Teller Effect. The splitting results in symmetric double potential wells for the lower level, with one side of the well corresponding to one enantiomer and the other side to its mirror image, and with equal probability for each. It will be shown that the discrimination of one enantiomer from the other may be assisted either by the neutral-current coupling to nuclear weak interaction or by a second-order radiative $interaction1$ both of which have pseudoscalar symmetry. It was found that only a limited class of molecules are amenable to this phenomenon. They belong to $D2d,D4d,D6d,S4$, and $S8$. Spin singlet and doublet states are both considered. For $odd-electron2$ and transformation of spin $functions3$, the most general selection rule consistent with time-reversal is derived. New tabulation is given to correct some misconceptions and minor errors in existing literature.