Two-photon ionization of atomic systems treated by means of the complex coordinate method

Abstract
A L2 discretization of the continuum within the scope of the complex coordinate technique is employed to obtain the differential cross section for two-photon ionization of atomic systems. The method avoids explicit construction of the continuum final state and instead dispersion relations are utilized to evaluate the appropriate transition matrix element controlling the process, to second order of perturbation theory in the nonrelativistic dipole approximation. The method is applied to the two-photon ionization of atomic hydrogen.