Many-body calculations of photodetachment cross sections of negative atomic and diatomic ions

Abstract

Polarizabilities and photodetachment cross sections are computed for the ground state of the halogen ions F- and Cl-, and for their isoelectronic diatomic hydrides OH- and SH-. The present work is based on the use of basis sets and on an integral equation that relates the real polarizability on the imaginary frequency axis to the photodetachment cross section. In order to compute the polarizability many-body perturbation theory has been used and the perturbation expansion is completed to second order in the Coulomb interaction. The continuum is represented by a finite set of discrete virtual states. In this way the difficult problem of obtaining continuum orbitals for two-center systems is avoided, and a high degree of electron correlation is included.