A perturbation-variation study of photodetachment from H-

A perturbation-variation method is used to calculate the cross section for photodetachment in H - over a comprehensive set of electron energies in the range 0.001-0.70 Ryd. The wavefunctions used are of high accuracy in that an accurate eigenenergy for the bound state of H - is obtained and the tail of the valence orbital is accurately calculated. The 1 P phaseshifts for the continuum wavefunction are also obtained to high accuracy. Only over a narrow energy range do the cross sections calculated using the length and velocity formulations differ by more than 1% and the difference never exceeds 1.4%. The discrepancy between the present photodetachment cross sections and those calculated by Broad and Reinhardt (1976) is small but rises to 4% at 0.7 Ryd.