Polarization effects in low-energy electron scattering from silane molecules in an exact static-exchange model

We have investigated the effects of various model polarization potentials in low-energy (below 15 eV) electron-SiH₄ collisions in which electron-exchange correlation is treated exactly via an iterative procedure. Two models of the parameter-free polarization potential are employed; one, the VₚₒₗJT potential, introduced by Jain and Thompson [J. Phys. B 15, L631 (1982)], is based on the polarized-orbital theory; the other, the correlation-polarization potential VₚₒₗCP, first proposed by O'Connel and Lane [Phys. Rev. A 27, 1893 (1983)], is given as a density functional. In this low-energy region, the differential as well as integral cross sections are greatly influenced by such short-range-correlation and long-range-polarization interactions. We found that a local parameter-free model to mimic charge-distortion effects is quite successful if it is determined under the polarized-orbital-type approach rather than based on density-functional theory.