The interaction of optically active molecules

The difference in interaction energies between two laevo molecules, and one dextro and one laevo, are analysed. Formulae are given for the discriminating terms in the dispersion and induction energies for molecules in fixed orientations, between freely rotating molecules, and molecules rotating about the intermolecular axis. Discrimination in the resonance interaction between optical isomers appears in the retarded interaction (in dipole approximation) as a term with an inverse square dependence on dis­tance in the near zone. Its significance is discussed for pairwise interactions and in crystalline systems.