X-ray photoionization of hydrogen in the presence of a low-frequency laser field is studied using an approach which partially takes into account the radiative stimulated corrections to both bound and continuum states. Special attention is paid to the cases in which one low-frequency photon is exchanged (absorbed or emitted) between the atomic system and the laser field. It is demonstrated that atomic ‘‘dressing’’ effects are important close to the ionization threshold.

• Received 26 May 1992

DOI:https://doi.org/10.1103/PhysRevA.47.1830