Elastic-electron-scattering cross sections forN2from 0 to 1000 eV. Energy-dependent exchange potentials

Integrated and differential cross sections for vibrationally elastic $e^{-}$-${\mathrm{N}}_2$ scattering from 0 to 1000 eV are calculated by means of the continuum multiple-scattering method (CMSM) with the Hara free-electron-gas and semiclassical exchange approximations. The present results represent a significant improvement over earlier CMSM calculations employing the Slater $X\alpha$ exchange approximation. The physical basis for this improvement is discussed. Resonance structures appear at 2.4, 13, and 26 eV in the ${\pi }_g$, ${\delta }_g$, and ${\sigma }_u$ channels, respectively; however, the latter two are very weak and only the ${\sigma }_u$ resonance has been observed in elastic scattering. Agreement between the present calculation and experiment is good over the entire energy range, although at fixed (equilibrium) internuclear distance, the ${\pi }_g$ resonance is too narrow and high. The agreement at the ${\pi }_g$ resonance is significantly improved by taking into account the effects of nuclear motion in the adiabatic nuclei approximation.