Interaction potentials and energy transfer cross sections for collisions of metastable helium and neon I: He(23 S)+Ne

Abstract

Differential cross sections have been measured for He(23 S)+Ne at kinetic energies between 28 and 370 meV. For energies above 90meV the elastic cross sections show Stuckelberg oscillations from curve crossings, which lead to the energy exchange process: He(23 S)+Ne→He(11 S)+Ne(2p 5 4s,3d,4p). Differential cross sections for this inelastic process could be measured above 200 meV. A fit to the data gives the potentials for He(23 S)+Ne and, less accurately, for He+Ne*. These results offer a simple explanation, why the exothermic pumping process of the infrared lines of the HeNe laser has a threshold of about 80 meV and a small cross section.