Photodetachment of the hydrogen and positronium negative ions

The photodetachment of the H-infinity(-), T-, D-, H-1(-), Mu(-) and Ps(-) ions by low-energy photons is considered in terms of the two-body cluster approximation. For all considered systems the constant C in the asymptotic form of the actual three-body wavefunction is determined from highly accurate, completely non-adiabatic wavefunctions. This constant plays a central role in this method, since it allows one to determine the photodetachment cross-sections for each of the considered ions. The computed photodetachment cross-section for the H-infinity(-) and Ps(-) ions agree quite well with the results of earlier studies. The photodetachment of the T-, D-, H-1(-) and Mu(-) ions with finite nuclear masses is also considered. The photodetachment of the H- ions is of great interest in astrophysics, since it determines the continuous spectra of our Sun and, in general, of all K-, G- and late F-type stars.