Chiral effects in the scattering of electrons by molecules

Abstract

There are a number of scattering phenomena that depend on the "handedness" of the scattering system. In this paper we concentrate on the elastic scattering of polarized electrons by closed-shell molecules and consider mainly the property of electron optic dichroism. The effects can be fully analysed using the general invariance properties of the scattering matrix under spatial inversion, time reversal, and rotations. However, there is still considerable discussion about the physical mechanism causing the effects. Among the models proposed are two involving the spin–orbit interaction; in one the bound orbitals are perturbed, and in the other the incident electron. In this paper we show how these two approaches can be combined in a unified treatment. We set up the scattering equation including exchange and spin–orbit in a consistent manner and identify which terms contribute to the chiral effects.