Elastic and vibrational differential cross sections for collisions of low- and intermediate-energy electrons with silane

Abstract

Absolute elastic differential cross sections for electron collisions with silane (SiH4) have been determined for incident electron energies of 1.8, 2.15, 2.65, 3, 4, 5, 7.5, 10, 15, 20, 40 and 100 eV over a scattering angular range of 20-130'. The measured angular distributions have been found to correspond quite well with the results of approximate theories employing either a multiple scattering formalism or an optical potential. Angular and energy distributions as well as vibrational excitation functions obtained with electrons of about 1.5-7 eV reveal the existence of a Si-H sigma * shape resonance with a maximum at around 1.8-2.2 eV in the t2 component of the scattered electron state. As predicted by a selection rule the same resonance is found in vibrational excitation functions obtained with electrons in this energy range. A multiple scattering calculation has been used to explain details of the resonance structure.