TY - JOUR

T1 - Above-threshold ionization in the x-ray regime

AU - Varma, Hari R.

AU - Ciappina, Marcelo F.

AU - Rohringer, Nina

AU - Santra, Robin

PY - 2009/11/30

Y1 - 2009/11/30

N2 - Two-photon above-threshold ionization processes in the x-ray regime are studied using atomic hydrogen as a model system. Within the minimal-coupling formalism of nonrelativistic quantum electrodynamics, two distinct interactions- Â □ p̂ in second order and Â 2 in first order-contribute to the two-photon absorption amplitude. The relative importance of these two interactions is assessed. It is found that above a photon energy of 6.8 keV, the contribution from Â 2 to the total two-photon absorption cross section dominates. In this high-energy regime, above-threshold ionization is a nonsequential purely nondipole process. Rate equations are employed to calculate the probabilities of ionization by Compton scattering, one-photon absorption, and two-photon absorption.

AB - Two-photon above-threshold ionization processes in the x-ray regime are studied using atomic hydrogen as a model system. Within the minimal-coupling formalism of nonrelativistic quantum electrodynamics, two distinct interactions- Â □ p̂ in second order and Â 2 in first order-contribute to the two-photon absorption amplitude. The relative importance of these two interactions is assessed. It is found that above a photon energy of 6.8 keV, the contribution from Â 2 to the total two-photon absorption cross section dominates. In this high-energy regime, above-threshold ionization is a nonsequential purely nondipole process. Rate equations are employed to calculate the probabilities of ionization by Compton scattering, one-photon absorption, and two-photon absorption.

UR - http://www.scopus.com/inward/record.url?scp=70949094490&partnerID=8YFLogxK

U2 - 10.1103/PhysRevA.80.053424

DO - 10.1103/PhysRevA.80.053424

M3 - 文章

AN - SCOPUS:70949094490

SN - 1050-2947

VL - 80

JO - Physical Review A - Atomic, Molecular, and Optical Physics

JF - Physical Review A - Atomic, Molecular, and Optical Physics

IS - 5

M1 - 053424

ER -