Interaction potential and reaction dynamics of He(21S, 23S)+Ne, Ar by the crossed molecular beam method

Abstract

Differential elastic scattering cross sections of metastable He(21S) and He(23S) with Ne and Ar were measured at thermal collision energies by the crossed molecular beam method. The interaction potentials of these systems are found to be similar to those of alkali-rare gas systems. The excitation transfer from He(21S) to Ne and the Penning and associative ionization processes in He(21S,23S) and Ar collisions only occur when interatomic distances are shorter than given critical values and interaction potentials are repulsive. The ratios of associative to Penning ionization cross sections were also measured for collisions of metastable He(21S,23S) and Ar as a function of collision energies. These results combined with the opacity function derived from differential elastic scattering cross sections of He(21S,23S) and Ar provide some information on the long range interaction of He+Ar+.