A complex rotated approach to resonant electron scattering on atoms in a static exchange plus polarisation formulation

Abstract

The authors propose the use of the complex coordinate method in conjunction with a local-density, X alpha static exchange plus polarisation model for the analysis of shape resonances in electron-atom scattering with possible extension to electron-molecule collisional processes. The basic model is discussed and the X alpha formalism is briefly reviewed. The authors investigate the inclusion of polarisation and exchange terms for the study of shape resonances in electron-atom scattering. By the use of the exterior complex scaling technique, complex resonance poles of the partial-wave S matrix can be directly evaluated in the positive lower half of the complex energy plane on the second Riemann sheet. The method is illustrated by presenting numerical investigations of the e-Be and e--Mg scattering systems. The behaviour of the partial-wave cross section and its dependence on the corresponding partial-wave S-matrix poles are discussed. Furthermore, the authors examine the appearance of asymmetries in the cross section in the vicinity of the poles.