Oscillator strengths and electron-excitation cross sections for atomic nitrogen

Abstract

The $\mathrm{LS}$ states belonging to the configurations ${2s}^{2}{2p}^{3},$ ${2s2p}^{4},$ ${2s}^{2}{2p}^{2}3s,$ ${2s}^{2}{2p}^{2}3p,$ ${2s}^{2}{2p}^{2}3d$, and ${2s}^{2}{2p}^{2}4s$ of neutral nitrogen are considered in the calculations of excitation energies and oscillator strengths. Extensive configuration interaction wave functions are used, which give excitation energies in close agreement with the experiment. The calculation of the differential and integral cross sections of the forbidden ${}^{4}{S}^{o}{\ensuremath{-}}^{2}{D}^{o}$ transition for the scattering of electrons from atomic nitrogen is performed in a 11-state close-coupling approximation using the R-matrix method in the energy region from threshold to 70 eV. The calculated differential cross sections are peaked in the backward direction and compare very well with the recent measurement. The present integral cross sections also show very good agreement with the available other calculations and measurement.