Penning and associative ionizationof argon atoms by excited metastable neon

Abstract

The associative-to-Penning ionization cross section ratio issimulated with a classical model for theNe*(3P2,0)-Ar collision. We used the semi-classicaloptical potential curve of Gregor and Siska together with calculated ab initio Ne-Ar+ potential curves todescribe the entry and exit channels, respectively. Thismodel which had already been adjusted to fit the total crosssection failed to reproduce both the experimental associativeionization cross section and the associative-to-Penning ionization cross section ratio. The contrasting results obtained between theory and experimental data are understood to bethe result of an unsuitable real part of the potential for theentrance channel. We did not attempt to modify the averagesemi-classical potential to fit the experimental data,and it is concluded that an accurate ab initio complexpotential is needed for a quantitative analysis of all theobservable quantities.