Ab initiocalculation of the asymmetric electron transfer cross section in the low velocity collision

Abstract

The (HeLi) 4+ one-electron molecule has been studied and the electronic energies of the states n = 1-5 have been determined as a function of the distance R between the two nuclei, in the Born-Oppenheimer approximation. The radial and rotational matrix elements for electron transfer in the Li 3+ + He + collision have been computed and the system of 35 coupled equations describing the collision in the impact parameter approximation has been solved for an initial system composed of an incident Li 3+ ion and a He + target in the ground state. The signs of the different terms appearing in the radial matrix elements have been carefully re-examined and a clear resonance induced by the avoided crossing of the 5dσ and 4pσ states has been proven. The Li 3+ + He + → Li 2+ + He 2+ total electron transfer cross section is found to lie between those of the adjacent symmetric systems He 2+ + He + and Li 3+ + Li 2+ and, in this respect, may be called 'quasisymmetric transfer'.