Laser effects in photoionization. II. Numerical solution of coupled equations for atomic hydrogen

The time-dependent Schrödinger equation was solved numerically, as a set of coupled equations, for an electron moving in three spatial dimensions, bound initially in the ground state of a hydrogen atom, and acted upon by a linearly polarized, single-frequency, classical electromagnetic field, turned on abruptly at t=0. Characteristic photoionization times ${\mathrm{\tau }}_{\mathrm{PI}}$ were computed for a wide range of laser intensities, at a photon energy of 5 eV. Comparison was made with the predictions of two widely used analytic expressions for ${\mathrm{\tau }}_{\mathrm{PI}}$. Emitted electron energy spectra and angular distributions were computed. The spectrum of radiation emitted during ionization was also determined.