Theory of x-ray absorption by laser-dressed atoms

Journal Article · Thu Mar 15 00:00:00 EDT 2007 · Physical Review. A

DOI:https://doi.org/10.1103/PHYSREVA.75.033412· OSTI ID:20982360

Buth, Christian; Santra, Robin ^[1]

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1. Argonne National Laboratory, Argonne, Illinois 60439 (United States)

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.

• OSTI ID: 20982360
• Journal Information: Physical Review. A, Vol. 75, Issue 3; Other Information: DOI: 10.1103/PhysRevA.75.033412; (c) 2007 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 1050-2947
• Country of Publication: United States
• Language: English

Related Subjects

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