Excitation of the fine-structure levels of atomic oxygen by slow electrons

Abstract

Calculations of cross sections for the excitation of fine-structure levels of the ground ${}_{}{}^3{}_{}{}^{}P$ state of atomic oxygen by electron impact in the energy range of 500-15 000 K are obtained by a close-coupling method. Below 3000 K, it is necessary to allow for energy differences between the fine-structure levels. Above 3000 K, polarization effects have been incorporated by use of pseudostates and are found to decrease the cross sections slightly. Collision strengths are a factor of 3-5 lower than those obtained by Breig and Lin. In view of recent multiconfiguration results of Saraph, our single-configuration calculations probably represent a lower limit to the fine-structure collision strengths.