Two-photon ionization ofH2

Abstract

The nonresonant-multiphoton-ionization problem for a diatomic molecule is formulated as the one-photon ionization of a perturbed orbital. The continuum and perturbed orbitals are calculated in the "frozen-core" Hartree-Fock potential of the molecular ion. These orbitals are expanded in spherical harmonics about the internuclear center of mass, and the projected, coupled radial equations are solved iteratively. The radial perturbed orbitals are obtained in every iteration using an exact Green's function calculated in the diagonal, local elements of the potential matrix. This step is of some interest since use of the Green's function to achieve, implicitly, the summations over complete sets of intermediate states has previously been confined to Coulomb or quantum defect method modified-Coulomb problems.