SCF treatment of charge polarization effects in intermediate-energy electron scattering calculations with applications to N2

Abstract

We report converged rotational close coupling calculations of the differential, integral, and momentum-transfer cross sections for seven model potentials for electron–N2 scattering at an impact energy of 30 eV. The model potentials involve a static potential calculated by the INDO/1s or INDOXI/1s method, an exchange potential calculated by the semiclassical exchange approximation from the INDO/1s or INDOXI/1s unperturbed electronic density, and a polarization potential. The polarization potentials used include the Buckley–Burke semiempirical one and various modifications of the INDOXI and INDO self-consistent-field adiabatic polarization potentials. We are able, without adjusting parameters, to obtain good agreement with the angle dependence of the experimentally measured sum of the elastic and rotational excitation differential cross sections although the absolute value of our calculated cross sections is about 20%–30% larger than the measured values in the best case, perhaps indicating that the model potentials are too strong or should have a nonzero imaginary part. We discuss the sensitivity of the computed results to details of both the static and polarization parts of the model potentials, and we present some predictions of the rotationally resolved state-to-state cross sections.