R-MATRIX CALCULATION FOR ELECTRON METHANE SCATTERING CROSS-SECTIONS

A recently developed technique for calculating cross sections in electron-molecule collision processes based on variational R-matrix theory is discussed. One of the main advantages of this method is its applicability to polyatomic systems. As a first example, integral and partial cross sections for the e- + CH4 system below the ionization limit and in the energy range of the Ramsauer minimum are presented. In addition, the corresponding eigenphases are shown. All calculations are based on the fixed-nuclei approximation. The paper is concluded by an analysis of the Ramsauer minimum with respect to the angular dependency of the differential cross sections in that energy region.