Relativistic effects in the non-resonant two-photon K-shell ionization of neutral atoms

NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS

卷:408

Article; Proceedings Paper

Hofbrucker, J.^1,2  Volotka, A. V.^2,3  Fritzsche, S.^1,2 

[1] Friedrich Schiller Univ Jena, Theoret Phys Inst, Max Wien Pl 1, D-07743 Jena, Germany

[2] Helmholtz Inst Jena, Frobelstieg 3, D-07743 Jena, Germany

[3] St Petersburg State Univ, Dept Phys, Oulianovskaya 1, St Petersburg 198504, Russia

关键词: Multi-photon ionization;    Light-matter interaction;    Relativistic effects in atoms;    Electronic transitions;   

DOI  :  10.1016/j.nimb.2017.03.153

来源: Elsevier

【 摘 要 】

Relativistic effects in the non-resonant two-photon K-shell ionization of neutral atoms are studied theoretically within the framework of second-order perturbation theory. The non-relativistic results are compared with the relativistic calculations in the dipole and no-pair approximations as well as with the complete relativistic approach. The calculations are performed in both velocity and length gauges. Our results show a significant decrease of the total cross section for heavy atoms as compared to the non relativistic treatment, which is mainly due to the relativistic wavefunction contraction. The effects of higher multipoles and negative continuum energy states counteract the relativistic contraction contribution, but are generally much weaker. While the effects beyond the dipole approximation are equally important in both gauges, the inclusion of negative continuum energy states visibly contributes to the total cross section only in the velocity gauge. (C) 2017 Elsevier B.V. All rights reserved.

【 授权许可】

Free