2007/06/30 by J. H. Bauer, Jarosław H Bauer · 18 citations
Physics and Astronomy · #Amplitude #Dipole #Electron #Field (mathematics) #Ionization #Laser-Matter Interactions and Applications #Laser-Plasma Interactions and Diagnostics #Photoionization #Photoionization mode #Quantum and Classical Electrodynamics #physics.atom-ph
paper · pdf · doi:10.1088/0953-4075/41/18/185003
published in Journal of Physics B Atomic Molecular and Optical Physics 41(18), 185003 (IOP Publishing) · The paper was initially submitted (in a previous version) on 16 October 2006 to J. Phys. A and rejected. This is the extended version (with 2 figures), which is identical to the paper published online on 12 December 2007 in Physica Scripta
openalex publication_date 2008/09/03 · arxiv created 2010/02/17 · arxiv updated 2015/05/12 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
We numerically compare ionization rates and photoelectron energy spectra resulting from the so-called length gauge (LG) and velocity gauge (VG) forms of the Keldysh–Faisal–Reiss (KFR) theory for a circularly polarized laser field. To this end, we use the well-known analytical formulae for the ground state of a hydrogen atom and we derive analogous formulae for its first excited (degenerate) state. It appears that both forms of the KFR theories show qualitatively different behaviour of ionization rate as a function of frequency and intensity of the laser field. In the LG KFR theory, one obtains much smaller stabilization of the hydrogen atom than in the VG KFR theory. Unlike the latter one, the LG KFR theory shows that for sufficiently strong laser field (in the non-relativistic and dipole approximations) ionization rate from a given initial state is only a function of intensity, but not of frequency of the laser field. We also find substantial differences in the shape of photoelectron energy spectra for both theories. In contrast to the VG KFR theory, the LG one shows a minimum in photoelectron energy spectra for some initial states of the hydrogen atom. We discuss our results by comparing them, where possible, to other theoretical calculations.