Two-photon detachment of electrons from halogen negative ions

Abstract

Absolute two-photon detachment cross sections and photoelectron angular distributions are calculated for halogen negative ions within lowest-order perturbation theory. The outer np ground-state wavefunctions are determined using the Dyson equation method. The ab initio correlation potential is scaled by introduction of a free parameter. We choose it to ensure that the np wavefunctions have a proper asymptotic behaviour P(r)exp(- r), corresponding to correct (experimental) binding energies Eb = 22/2m. The latter is crucial for obtaining correct absolute values of the multiphoton cross sections (Gribakin and Kuchiev 1997 Phys. Rev. A 55 3760). Comparisons with previous calculations and experimental data are performed.