ELECTRON-SCATTERING WITH H2S AND PH3 MOLECULES

Calculated total, differential and momentum transfer cross sections are reported for the vibrationally elastic scattering of electrons from H2S and PH3 molecules in the range of energy 0.1-50 eV. The scattering process is approximated by two incoherent scatterings caused, separately, by a central field and a long-range electric dipole interaction. The central field is calculated with a spherical approximate molecular wave function, in which the exchange interaction is treated in two ways: (i) exactly within the accuracy of the molecular wave function; (ii) approximately by a local model potential. The scattering by the central field is calculated with partial wave expansion technique, while the scattering by the electric dipole potential is calculated by using the first Born approximation for a rotating dipole model with experimental values of the dipole moments of H2S and PH3. The total cross sections are approximated by the incoherent sum of the cross section due to the central potential and the cross section of 00 --> 10 rotational transition caused by the electric dipole potential. The effects of the polarization interaction are also tested. The contribution of small-angle scattering to the integral cross section is analyzed for these weakly polar molecules with some quantitative comparison.