Calculation of cross sections for vibrational excitation and dissociative attachment in HCl and DCl beyond the local-complex-potential approximation

Abstract

Cross sections for vibrational excitation and dissociative electron attachment in the collision of low-energy electrons with HCl and DCl are calculated using a resonance model which includes the effects of the long-range dipole potential. The parameters of the model are determined by a least-squares fit of the fixed-nuclei eigenphase sum to recent ab initio data of Padial and Norcross. The nuclear dynamics in the short-lived collision complex is treated without resorting to the local approximation for the decay width and the level shift. The resulting integral cross sections for vibrational excitation and dissociative attachment are in semi-quantitative agreement with the available experimental data, both with respect to the energy dependence and the absolute magnitude of the cross sections. The accuracy of the widely used adiabatic-nuclear-vibration approximation is quantitatively assessed for this prototypical electron-polar-molecule collision system.