Topological phase and interference effects in slow and charge-exchange collisions

The impact parameter dependence of the transition probability for and electron transfer reactions at collision energies of 3 and , respectively, is calculated within the advanced adiabatic method with inclusion of the dynamical phases and the topological phase associated with the corresponding hidden-crossing branch point of the adiabatic electronic energy in the complex plane of internuclear distance. The results of the calculations are compared with those of multi-channel close-coupling calculations based on a molecular-orbital expansion. The effect of the topological phase is to alternate the oscillatory structure of the transition probability.