Beyond the dipole approximation for helium and hydrogen in intense laser fields

Abstract

We present a practical and efficient computational method for the solution of the time-dependent full-dimensionality Schrödinger equation for two-electron atoms in intense laser fields. The method, incorporating electric quadrupole and magnetic dipole terms, is a generalization of an approach within the dipole approximation that has previously found successful application at wavelengths from the visible to the XUV. We discuss the computational demands of non-dipole calculations for helium. We deduce from our helium formulation the equivalent formulation for hydrogen and report calculations we have performed on this atom beyond the dipole approximation, producing results that are found to be in good agreement with literature values obtained by a different method.