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Title: Theory of x-ray absorption by laser-dressed atoms

Abstract

An ab initio theory is devised for the x-ray photoabsorption cross section of atoms in the field of a moderately intense optical laser (800 nm, 10{sup 13} W/cm{sup 2}). The laser dresses the core-excited atomic states, which introduces a dependence of the cross section on the angle between the polarization vectors of the two linearly polarized radiation sources. We use the Hartree-Fock-Slater approximation to describe the atomic many-particle problem in conjunction with a nonrelativistic quantum-electrodynamic approach to treat the photon-electron interaction. The continuum wave functions of ejected electrons are treated with a complex absorbing potential that is derived from smooth exterior complex scaling. The solution to the two-color (x-ray plus laser) problem is discussed in terms of a direct diagonalization of the complex symmetric matrix representation of the Hamiltonian. Alternative treatments with time-independent and time-dependent non-Hermitian perturbation theories are presented that exploit the weak interaction strength between x rays and atoms. We apply the theory to study the photoabsorption cross section of krypton atoms near the K edge. A pronounced modification of the cross section is found in the presence of the optical laser.

Authors:
;  [1]
  1. Argonne National Laboratory, Argonne, Illinois 60439 (United States)
Publication Date:
OSTI Identifier:
20982360
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review. A; Journal Volume: 75; Journal Issue: 3; Other Information: DOI: 10.1103/PhysRevA.75.033412; (c) 2007 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
74 ATOMIC AND MOLECULAR PHYSICS; ABSORPTION; CROSS SECTIONS; ELECTRONS; EXCITED STATES; HAMILTONIANS; HARTREE-FOCK METHOD; KRYPTON; LASER RADIATION; MATHEMATICAL SOLUTIONS; MODIFICATIONS; PERTURBATION THEORY; PHOTON-ATOM COLLISIONS; PHOTON-ELECTRON INTERACTIONS; QUANTUM ELECTRODYNAMICS; RADIATION SOURCES; TIME DEPENDENCE; WAVE FUNCTIONS; WEAK INTERACTIONS; X RADIATION; X-RAY SPECTRA

Citation Formats

Buth, Christian, and Santra, Robin. Theory of x-ray absorption by laser-dressed atoms. United States: N. p., 2007. Web. doi:10.1103/PHYSREVA.75.033412.
Buth, Christian, & Santra, Robin. Theory of x-ray absorption by laser-dressed atoms. United States. doi:10.1103/PHYSREVA.75.033412.
Buth, Christian, and Santra, Robin. Thu . "Theory of x-ray absorption by laser-dressed atoms". United States. doi:10.1103/PHYSREVA.75.033412.
@article{osti_20982360,
title = {Theory of x-ray absorption by laser-dressed atoms},
author = {Buth, Christian and Santra, Robin},
abstractNote = {An ab initio theory is devised for the x-ray photoabsorption cross section of atoms in the field of a moderately intense optical laser (800 nm, 10{sup 13} W/cm{sup 2}). The laser dresses the core-excited atomic states, which introduces a dependence of the cross section on the angle between the polarization vectors of the two linearly polarized radiation sources. We use the Hartree-Fock-Slater approximation to describe the atomic many-particle problem in conjunction with a nonrelativistic quantum-electrodynamic approach to treat the photon-electron interaction. The continuum wave functions of ejected electrons are treated with a complex absorbing potential that is derived from smooth exterior complex scaling. The solution to the two-color (x-ray plus laser) problem is discussed in terms of a direct diagonalization of the complex symmetric matrix representation of the Hamiltonian. Alternative treatments with time-independent and time-dependent non-Hermitian perturbation theories are presented that exploit the weak interaction strength between x rays and atoms. We apply the theory to study the photoabsorption cross section of krypton atoms near the K edge. A pronounced modification of the cross section is found in the presence of the optical laser.},
doi = {10.1103/PHYSREVA.75.033412},
journal = {Physical Review. A},
number = 3,
volume = 75,
place = {United States},
year = {Thu Mar 15 00:00:00 EDT 2007},
month = {Thu Mar 15 00:00:00 EDT 2007}
}