Exchange Effects on the Rotational Excitation of HCl by Electron Collisions

Abstract

An effect of electron exchange is explicitly included in the calculation of the rotational (0→1) and elastic cross sections of HCl. For a rotational excitation, a considerable effect appears only in the s - and p -wave partial cross sections in a somewhat higher energy region (\(E{\gtrsim}1\) eV). Because of the dominance of the higher-partial wave contribution in the electron-polar molecule collision, the total excitation cross section is little affected (only a few per cent) by the electron exchange, even in this higher-energy range. The differential cross section at large angles, however, changes with inclusion of the exchange effect. For an elastic scattering, the electron exchange strongly influences the cross section. Especially, in the energy region where a potential resonance occurs, the value of the elastic cross section is increased by a factor of 10.