Molecular autoionisation width for He(31P)+Ne: Penning and associative ionisation cross sections

Abstract

Associative and Penning ionisation cross sections sigma _A4dI and sigma _PI and their sum sigma _TI= sigma _AI+ sigma _PI are calculated for collisions of Ne with radiative excited He^*(3¹P) in the energy range 0.025-0.21 eV, in the classical impact parameter formulation. It is shown that the energy dependence of the sigma _Al cross section previously measured in a crossed-beam apparatus in the authors; laboratory and the velocity-average quenching cross sections sigma _TI obtained in discharges can be explained in terms of an autoionisation width for (HeNe)* which includes simultaneous direct and exchange mechanisms and is saturated in the small-R region.