Coupling of molecular spin in electron-molecule scattering

Abstract

We consider spin-dependent effects in low-energy elecvan molecule scattering. Until now no explicit spin dependent effects have been included in ob initio calculations. We discuss the fine-structure effect, well known from atomic physics, for diatomic molecules as a model which can describe deviations from pure exchange scattering. Numerical mulls for the a 3 n excitation of CO will give an indication of the magnitude of the effects. Resolving the finestructure of h e tuget leads to h e different coupling schemes for diatomic molecules. We consider in this paper Hund's cases (a) and (b) as the two most important ones. In particular. differential cross sections and spin polarization for unpolarized projectiles and targets are discussed. For molecules obeying Hund's cf&e (a) coupling scheme orientation and alignment parameters are inuoduced.