Theoretical cross sections for collisional angular momentum transfer in atomic Rydberg states

Abstract

A simple semiclassical model already proposed by Gersten (1976) and Omont (1977) is used for the calculation of the angular momentum transfer in collisions of hydrogenic Rydberg states with rare gases. The model, which uses a Fermi pseudopotential, is applied to the quenching of (n=8-14) D states of Na by He and Ne, and is found to be in rough agreement with experiment when n>or approximately=10. The main new fact to be noted is the prediction that all L (angular momentum) changing cross sections have the same order of magnitude, whatever the final value of L. The physical basis of the model is discussed. It is simply shown that the Fermi pseudopotential and binary encounter methods are unable to predict slightly inelastic transfer cross sections ( Delta E greater than a few tens of cm^-1).