SINGLE-ELECTRON DETACHMENT FROM H- BY PROTON IMPACT

We are concerned with the basic single electron detachment process H+ H- --> H+ + H(1s) + e at incident velocities upsilon ranging from th e threshold 0.235 au to 10 au. It has been known for more than two dec ades, that the eikonal Coulomb-Born (ECB) approximation of Gayet, Jane v and Salin is in disagreement, by two-three orders of magnitude, with the experiment of Peart, Grey and Dolder. Moreover, the total cross s ections of the ECB method tend to a constant value at large incident v elocities upsilon, in sharp contrast with the corresponding proper Bet he asymptote upsilon(-2) ln upsilon(2). This is unexpected since the E CB model properly includes the long-range Coulombic effects in both th e entrance and exit channels. We reinvestigated the problem and found that the initial scattering state in the ECB model is inconsistent wit h the perturbation potential which causes the transition in the ''prio r'' form of the T-matrix. When this basic deficiency of the theory is removed, a novel method called the modified Coulomb-Born (MCB) approxi mation emerges, which is found to be in good agreement with the measur ements.