Reexamination of multiphoton ionization of xenon under 12.7-eV radiation

We present a theoretical analysis of multiphoton ionization of xenon pertaining to experimental data obtained by free electron laser (FEL) radiation of photon energy 12.7 eV by Wabnitz et al. Phys. Rev. Lett. 94 023001 (2005)]. Taking also into consideration previous related theoretical information by Santra and Greene Phys. Rev. A 70 053401 (2004)], we present a detailed study of the dependence of ionic yields on radiation intensity as well as the expected saturation intensities. Our emphasis is on the basic features characterizing such processes and in spite of analysis in terms of various scenarios, we find that some incompatibility between theory and experiment persists.