Theory of multiphoton ionization tested on negative ions.

Abstract

In a recently published perturbation theory study of multiphoton-ionization cross sections of H{sup {minus}} (S. Geltman, Phys. Rev. A 43, 4930 (1991)), a serious discrepancy was reported between the model-based results and previous {ital ab} {ital initio} Floquet-theorem-based coordinate rotation results (M. Crance, J. Phys. B 23, L285 (1990)). We present two-and three-photon ionization cross sections from many-electron, many-photon-theory nonperturbative calculations, which essentially agree with Geltman's results. This finding supports our earlier conclusions on the physics of photodetachment without or with an external static field.