ELASTIC-SCATTERING OF ELECTRONS BY METHANE MOLECULES

Vibrationally elastic cross sections for electron collisions with CH4 are calculated with an ab initio electrostatic potential. Effects of e lectron exchange and target polarization are taken into account approx imately. Differential cross sections (DCS) are calculated for the elec tron energies 10-50 eV and compared with recent measurements. Comparin g with the result of a spherical potential model, effects of anisotrop y of the molecule are made clear. Integral and momentum-transfer cross sections are also calculated to see the validity of the extrapolation procedure taken in deriving those cross sections from experimental DC S.