Generalization of the Demkov formula in near-resonant charge transfer

Using the same method by which Dinterman and Delos (1977) have generalized the formula of Rosen and Zener for the near-resonant charge transfer transition probability in the noncrossing case, the authors have generalized the well known Demkov formula, removing most of its defects. They have compared the generalized Demkov formula to the direct numerical solution to the coupled Schrodinger equations for two actual ion-atom systems: Li + +Na and K + +Rb and have shown that the generalized formula is much better than the original Demkov formula and is in good agreement with the numerical results in a large region of velocities.