CRITICAL-STUDY OF PHOTODETACHMENT OF H- AT ENERGIES UP TO THE N=4 THRESHOLD

We apply the close-coupling method in terms of the hyperspherical coordinates;to the two-electron system H-. A two-dimensional matching procedure is used to connect the close-coupling wave function to an independent-electron wave function in the asymptotic region. The latter is described as the wave function of a detached electron moving in a dipole potential field of the neutral hydrogen atom. The total photodetachment cross sections and the partial cross sections for the production of the H atoms in different states n are calculated up to the n=4 hydrogenic threshold. The results obtained in the length and acceleration forms agree within about three significant figures. The magnitude and shape of the P-1 degrees shape resonance just above the n=2 threshold are found to depend sensitively on the initial-state wave function. This appears to be one of the reasons for a disparity among the cross sections in the literature. The present result improves greatly on the existing computational results. The relative magnitudes of the,partial cross sections for the production of H (n=1,2,3) atoms below the n=4 threshold are substantially different from the only previous results of the eigenchannel R-matrix calculations [H. R. Sadeghpour, C. H. Greene, and M. Cavagnero, Phys. Rev. A 45, 1587 (1992)]. The present results on both partial and total cross sections are in excellent agreement with experiments.