Two- and three-photon ionization in the noble gases

Abstract

By using a characteristic Green's function for an exactly solvable Schr\"odinger equation with an approximation to the central potential of Hermann and Skillman, the cross section for nonresonant two- and three-photon ionization of Ne, Ar, Kr, and Xe were calculated in $\mathrm{jl}$ coupling. Expressions for cross sections in $\mathrm{jl}$ coupling are given. Comparison with the Ar two-photon cross section of Pindzola and Kelly, calculated using the many-body theory, the dipole-length approximation, and $\mathrm{LS}$ coupling shows a disagreement of as much as a factor of 2. The disagreement appears to arise from distortion introduced by shifting the Green's-function resonances to experimental values.