Theory of photodetachment near fine-structure thresholds

High-resolution measurements of S- photodetachment near threshold are interpreted on the basis of an intermediate [p4(P3)+e(l=0)]P2 complex which dissociates into jj-coupled constituents. The e-S interaction is represented by doublet and quartet scattering lengths ad and aq. Relative cross sections are calculated in terms of electron energies, and of ad and aq. Thereby we generalize to a multichannel process the scattering-length theory of cross sections near s-wave thresholds. Many features of the experimental data are accounted for. Predictions are made on the spin-polarization effects of circularly polarized light. © 1971 The American Physical Society