Cross sections for the multiphoton ionization of sodium in a linearly polarized radiation field

Abstract

A calculation of the N-photon ionization cross sections with N=2,3,4,5 in the frequency interval 0.09836, 877 (1989)]. The final-state wave function represents the Volkov-like continuum, distorted by the atomic potential, while the initial state is described by the rotating-wave approximation with the inclusion of the ground-state 3s and two excited p states. The cross sections were calculated for two kinds of initial conditions: instantaneous and adiabatic switching of radiation. The results of the calculation with the distorted continuum wave functions representing the final state were compared to those obtained from Coulomb and plane-wave functions.