Excitation of thebΣu+3state ofH2by electron impact: Semiclassical exchange potentials at intermediate energies

Abstract

Integrated and differential cross sections for the excitation of the $b{}_{}{}^3{}_{}{}^{}\Sigma _u^{+}{}_{}{}^{}$ state of ${\mathrm{H}}_2$, from the ground state, by electron impact, are presented. The energy range of interest is 10.5 to 40.0 eV. The close-coupling equations for this process are solved in five different exchange approximations: exact two-electron exchange terms, no orthogonality; exact two-electron exchange terms, orthogonality; semiclassical exchange terms, no orthogonality, with barrier term; semiclassical exchange terms, no orthogonality, no barrier term; and semiclassical exchange terms, orthogonality, with barrier term. The purpose is to judge the reliability of the semiclassical exchange approximation for electronic excitation of molecules by electron impact at intermediate energies. The results are compared with recent theoretical estimates for the same process.