Angle-resolved photoelectron spectra, resulting from the strong-field ionization of atoms or molecules, carry a rich amount of information on ionization athways, electron dynamics, and the target structure. We have investigated angle-resolved photoelectron spectra arising from the nonresonant ionization of xenon Rydberg atoms in the multiphoton regime, using intense midinfrared radiation from a free-electron laser. The experimental data reveal a rich oscillatory structure in the low-order above-threshold ionization region. By performing quantummechanical and semiclassical calculations, the observed oscillations could be well reproduced and explained by both a multiphoton absorption picture as by a model invoking electron wave-packet interferences. Furthermore, we demonstrate that the shape and orientation of the initial Rydberg state leaves its own fingerprint on the final angular distribution.

Additional Metadata
Publisher APS
Persistent URL
Journal Phys. Rev. A
Huismans, Y, Rouzée, A, Gijsbertsen, A, Logman, P.S.W.M, Lépine, F, Cauchy, C, … Vrakking, M.J.J. (2013). Photoelectron angular distributions from the ionization of xenon Rydberg states by midinfrared radiation. Phys. Rev. A, 87(3, Article number: 33413), 1–10. doi:10.1103/PhysRevA.87.033413