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Title: Outstanding Spin-Orbit-Activated Interchannel Coupling in the Cs and Ba 3d Photoemission

Abstract

Partial 3d{sub 5/2} photoionization cross sections of atomic Cs and Ba as well as the asymmetry parameter {beta} of the angular distribution of the Cs 3d{sub 5/2} photoelectrons were investigated near the threshold of the 3d{sub 3/2} channel at about 750 eV and 800 eV, respectively. Strong electron correlations, in particular, the spin-orbit activated interchannel coupling between the 3d{sub 5/2} and 3d{sub 3/2} channels, govern the observed spectra. The most striking effect was found for {beta}{sub 5/2} of Cs with a dramatic increase from {beta}=1.0 to {beta}=1.5 in the energy region where the mixing between both channels causes a pronounced minimum in the partial 3d{sub 5/2} cross section. This result indicates the decisive influence of the interference term on the asymmetry parameter {beta} with its dependence on the phase difference between the outgoing p and f waves.

Authors:
; ;  [1];  [2];  [3]; ;  [4]
  1. Institut fuer Optik und Atomare Physik, Technische Universitaet Berlin, Hardenbergstrasse 36, 10623 Berlin (Germany)
  2. BESSY GmbH, Albert-Einstein-Strasse 15, 12489 Berlin (Germany)
  3. Science Faculty, Physics Department, Istanbul University, 34118 Vezneciler/Istanbul (Turkey)
  4. LIXAM, Centre Universitaire Paris-Sud, Batiment 350, 91405 Orsay Cedex (France)
Publication Date:
OSTI Identifier:
20951208
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review Letters; Journal Volume: 98; Journal Issue: 14; Other Information: DOI: 10.1103/PhysRevLett.98.143002; (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; ANGULAR DISTRIBUTION; ASYMMETRY; BARIUM; CESIUM; CROSS SECTIONS; ELECTRON CORRELATION; EV RANGE 100-1000; F WAVES; INTERFERENCE; L-S COUPLING; P WAVES; PHOTOEMISSION; PHOTOIONIZATION

Citation Formats

Richter, T., Heinecke, E., Zimmermann, P., Godehusen, K., Yalcinkaya, M., Cubaynes, D., and Meyer, M. Outstanding Spin-Orbit-Activated Interchannel Coupling in the Cs and Ba 3d Photoemission. United States: N. p., 2007. Web. doi:10.1103/PHYSREVLETT.98.143002.
Richter, T., Heinecke, E., Zimmermann, P., Godehusen, K., Yalcinkaya, M., Cubaynes, D., & Meyer, M. Outstanding Spin-Orbit-Activated Interchannel Coupling in the Cs and Ba 3d Photoemission. United States. doi:10.1103/PHYSREVLETT.98.143002.
Richter, T., Heinecke, E., Zimmermann, P., Godehusen, K., Yalcinkaya, M., Cubaynes, D., and Meyer, M. Fri . "Outstanding Spin-Orbit-Activated Interchannel Coupling in the Cs and Ba 3d Photoemission". United States. doi:10.1103/PHYSREVLETT.98.143002.
@article{osti_20951208,
title = {Outstanding Spin-Orbit-Activated Interchannel Coupling in the Cs and Ba 3d Photoemission},
author = {Richter, T. and Heinecke, E. and Zimmermann, P. and Godehusen, K. and Yalcinkaya, M. and Cubaynes, D. and Meyer, M.},
abstractNote = {Partial 3d{sub 5/2} photoionization cross sections of atomic Cs and Ba as well as the asymmetry parameter {beta} of the angular distribution of the Cs 3d{sub 5/2} photoelectrons were investigated near the threshold of the 3d{sub 3/2} channel at about 750 eV and 800 eV, respectively. Strong electron correlations, in particular, the spin-orbit activated interchannel coupling between the 3d{sub 5/2} and 3d{sub 3/2} channels, govern the observed spectra. The most striking effect was found for {beta}{sub 5/2} of Cs with a dramatic increase from {beta}=1.0 to {beta}=1.5 in the energy region where the mixing between both channels causes a pronounced minimum in the partial 3d{sub 5/2} cross section. This result indicates the decisive influence of the interference term on the asymmetry parameter {beta} with its dependence on the phase difference between the outgoing p and f waves.},
doi = {10.1103/PHYSREVLETT.98.143002},
journal = {Physical Review Letters},
number = 14,
volume = 98,
place = {United States},
year = {Fri Apr 06 00:00:00 EDT 2007},
month = {Fri Apr 06 00:00:00 EDT 2007}
}
  • This paper investigates for the first time ever the use of the spin-orbit interaction to probe correlation effects in the generalized oscillator strength (GOS) of the 3d subshells of Cs, Ba, and Xe, viz. we study how the GOSs of the Cs, Ba, and Xe 3d{sub 3/2} and 3d{sub 5/2} levels are affected by the intradoublet correlations. The calculations are carried out using the Hartree-Fock approximation and within the framework of a modified version of the spin-polarized random phase approximation with exchange, which takes into account multielectron correlation effects. The effects of relaxation of the excited electrons due to themore » creation of the 3d vacancy are also accounted for. Our GOS results for Cs, Ba, and Xe, obtained for values of the momentum transfer q from 0 to 4 a.u. and energy transfer {omega} from 0.1 to 8 Ry, demonstrate the strong interaction between the components of the spin-orbit doublet of the 3d electrons in Cs, Ba, and Xe. This leads to the appearance of an additional maximum in the GOS for the 3d{sub 5/2} subshell, due to the action of the 3d{sub 3/2} electrons. Additionally, for the dipole transition in Cs and Ba, the 3d{sub 5/2} subshell perturbs the 3d{sub 3/2} strongly for q=4 a.u. only, while in Xe, the perturbation is at the {omega} value of approximately 58 Ry for all considered q values. It is concluded that the intradoublet correlations are generally very important in the dipole, monopole, and quadrupole transitions, but particularly in the dipole transition.« less
  • We present spin-resolved 2p core level photoemission for the 3d transition metal films of Fe and Co grown on Cu(100). We observe clear spin asymmetry in the main 2p core level photoemission peaks of Fe and Co films consistent with trends in the bulk magnetic moments. The spin polarization can be strongly enhanced, by variation of the experimental geometry, when the photoemission is undertaken with circularly polarized light, indicating that spin-orbit interaction can have a profound in spin polarized photoemission. Further spin polarized photoemission studies using variable circularly polarized light at high photon energies, high flux are indicated, underscoring themore » value of synchrotron measurements at facilities with increased beam stability.« less
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  • The spin polarization parameters of photoelectrons from Xe, Cs, and Ba 3d{sub 5/2} and 3d{sub 3/2} levels are calculated using a modified version of the so-called spin-polarized random phase approximation with exchange. The effects of relaxation of excited electrons due to the creation of a 3d vacancy are also accounted for. We demonstrate that these parameters that characterize the photoionization process, as a function of the incoming photon frequency {omega}, acquire additional features when the interaction between electrons that belong to the 3d{sub 5/2} and 3d{sub 3/2} components of the spin-orbit doublet is taken into account. We conclude that throughmore » spin-orbit interaction polarization can be achieved and correlations probed.« less