PHOTODETACHMENT OF H- AND LI-

The photodetachment cross sections for H- and Li- in the vicinity of t he If(n=2-4) and Li(n=3-4) thresholds are calculated. A discrete numer ical basis set, combined with the method of complex rotation, isr used to construct highly correlated descriptions of both initial and final states. The energies and widths of the doubly excited states are calc ulated directly and compared with results from experiments and other c alculations when available: Other resonance parameters for photoexcita tion from the ground slate to the autodetaching states, describing the shape and the strength of the resonances, are-also calculated. Mass p olarization was considered for the doubly excited States of H-, but wa s found to be much smaller than the present experimental accuracy. The possibility of describing a photodetachment resonance with a Fano pro file, i.e., with a few resonance parameters connected to properties of a specific autodetaching state, is investigated and it is concluded t hat most resonances in Li- in the region studied, where overlapping re sonances are common, cannot be meaningfully analyzed in this way.