Low-energy electron-molecule scattering: Comparison of coupled channel treatments of e^-N₂ scattering at 13.6 eV using various approximations to the static and exchange potentials and an approximate polarization potential

We consider vibrationally and electronically elastic electron scattering by N₂ at 13.6 eV impact energy. We use four combinations (S, SP, SE, and SEP) of the static (S), exchange (E), and polarization (P) potentials, four target molecular orbital wave functions (INDO/1s, INO/1s with double zeta core, and Cade-Sales-Wahl and Ermler ab initio), and two local exchange approximations (semiclassical and Hara free-electron gas). We also consider the effect of using an accurate wave function for the spherical average and lowest order anisotropy and an INDO/1s wave function for higher order anisotropics, as well as other ambinations. The effects of approximations to the various terms in the interaction potential and the target wave function are illustrated by calculations of the partial integral cross sections.