Direct momentum-space calculations for the resonant multiphoton processes of a hydrogen atom under intense laser pulses.

Abstract

We present a momentum-space solution for the time-dependent Schr{umlt o}dinger equation of a realistic hydrogen atom in a strong laser pulse. The method can integrate the nonperturbative system to thousands of optical cycles, previously thought not yet feasible. A hydrogen atom under a 285-nm (4.357-eV), 97.5-TW/cm{sup 2} short pulse is found to produce two prominent photoelectron peaks above threshold, and significant intermediate bound-state resonance with the 4{ital p} state. With a 248-nm (5-eV) probe laser pulse that is ten times longer, the resonant structure is explored. {copyright} {ital 1996 The American Physical Society.}