Multistate Impact-Parameter Calculation of Atom-Atom Excitation Cross Sections: Excitation of Atomic Hydrogen by Neon, Argon, and Krypton

Abstract

Excitation cross sections for the collisions $\mathrm{H}\mathrm{}\left(1s\right)\mathrm{}$,+Ne, Ar, $\mathrm{Kr}\to \mathrm{H}(2s, 2p_0, 2p_{\pm })+\mathrm{N}\mathrm{e},\mathrm{ }\mathrm{A}\mathrm{r},\mathrm{ }\mathrm{Kr}$ are calculated over the velocity range of 0.3-5.0 a.u. in the distorted Born, two-state (for argon only), and four-state impact-parameter approximations that do not allow for electron exchanges between the colliding atoms. The results are compared with earlier first Born and scaled first Born calculations and with experimental data. The four-state cross sections, while greatly reduced from the first Born results, are still between three and ten times greater than experiment. Polarization fractions are also calculated from the four-state cross sections and compared with experimental data and with previous calculations.