Ionization of hydrogen atoms by intense vacuum ultraviolet radiation

J. Phys. B 34, 2245 (2001)

Jaroslaw Bauer, Lukasz Plucinski, Bernard Piraux, Robert Potvliege, Mariusz Gajda and Jacek Krzywinski

We study the ionization of hydrogen atoms by an intense pulsed beam of photons with energies of 17 or 50 eV. The work is motivated by the demonstration of the free-electron laser (FEL) action at the DESY Laboratory. The parameters chosen for the incident field are in the regime accessible by the FEL. Ionization yields are obtained within three different approaches, namely the strong-field approximation, the Floquet method and a numerical solution of the time-dependent Schrödinger equation. A marked stabilization effect for 50 eV photons is shown.