Elastic scattering of low-energy electrons from methane

Modified exact static-exchange calculations for the low-energy elastic scattering of electrons from methane are presented in the fixed-nuclei approximation using spherical approximate target wavefunctions. The exchange effect is included exactly. The distortion and polarisation of the target charge distribution are accounted for by a parameter-free correlation-polarisation potential. Total and differential cross sections are presented and the results are good. It is concluded that the correlation-polarisation potential adequately represents the interactions not included in the static-exchange formalism.