Abstract
The adiabatic and distortion approximations to a two-state treatment in the impact-parameter formulation of heavy-particle collisions are used to calculate the 2s and 2p single-excitation cross sections describing collisions between two ground-state hydrogen atoms with impact energy E in the range 360 ev E <or= 100 kev. Comparison with results of an exact two-state treatment shows that the adiabatic approximation accounts remarkably well for the effect of back-coupling, which is neglected in the distortion approximation and which assumes increasing importance as the impact energy is lowered.

This publication has 3 references indexed in Scilit: