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Title: Radiative electron capture into high-Z few-electron ions: Alignment of the excited ionic states

Abstract

We lay out a unified formalism for the description of radiative electron capture into excited states of heavy, few-electron ions and their subsequent decay, including a full account of many-electron effects and higher-order multipoles of the radiation field. In particular, the density-matrix theory is applied to explore the magnetic sublevel population of the residual ions, as described in terms of alignment parameters. For the electron capture into the initially hydrogenlike U{sup 91+} and lithiumlike U{sup 89+} uranium projectiles, the alignment parameters are calculated, within the multiconfiguration Dirac-Fock approach, as a function of the collision energy and for different ionic states. From these calculations, we find that the many-electron interactions may result in a small enhancement of the alignment, and that this effect becomes more pronounced for highly excited levels.

Authors:
; ; ;  [1];  [2];  [3]
  1. Max-Planck-Institut fuer Kernphysik, Saupfercheckweg 1, D-69117 Heidelberg (Germany)
  2. (GSI), D-64291 Darmstadt, Germany and Institut fuer Kernphysik, Universitaet Frankfurt, D-60486 Frankfurt (Germany)
  3. (Germany)
Publication Date:
OSTI Identifier:
20786922
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review. A; Journal Volume: 73; Journal Issue: 3; Other Information: DOI: 10.1103/PhysRevA.73.032716; (c) 2006 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; CATIONS; DECAY; DENSITY MATRIX; ELECTRON CAPTURE; ELECTRONS; EXCITED STATES; ION COLLISIONS; MULTIPOLES; URANIUM

Citation Formats

Surzhykov, Andrey, Jentschura, Ulrich D., Stoehlker, Thomas, Fritzsche, Stephan, Gesellschaft fuer Schwerionenforschung, and Institut fuer Physik, Universitaet Kassel, D-34132 Kassel. Radiative electron capture into high-Z few-electron ions: Alignment of the excited ionic states. United States: N. p., 2006. Web. doi:10.1103/PHYSREVA.73.0.
Surzhykov, Andrey, Jentschura, Ulrich D., Stoehlker, Thomas, Fritzsche, Stephan, Gesellschaft fuer Schwerionenforschung, & Institut fuer Physik, Universitaet Kassel, D-34132 Kassel. Radiative electron capture into high-Z few-electron ions: Alignment of the excited ionic states. United States. doi:10.1103/PHYSREVA.73.0.
Surzhykov, Andrey, Jentschura, Ulrich D., Stoehlker, Thomas, Fritzsche, Stephan, Gesellschaft fuer Schwerionenforschung, and Institut fuer Physik, Universitaet Kassel, D-34132 Kassel. Wed . "Radiative electron capture into high-Z few-electron ions: Alignment of the excited ionic states". United States. doi:10.1103/PHYSREVA.73.0.
@article{osti_20786922,
title = {Radiative electron capture into high-Z few-electron ions: Alignment of the excited ionic states},
author = {Surzhykov, Andrey and Jentschura, Ulrich D. and Stoehlker, Thomas and Fritzsche, Stephan and Gesellschaft fuer Schwerionenforschung and Institut fuer Physik, Universitaet Kassel, D-34132 Kassel},
abstractNote = {We lay out a unified formalism for the description of radiative electron capture into excited states of heavy, few-electron ions and their subsequent decay, including a full account of many-electron effects and higher-order multipoles of the radiation field. In particular, the density-matrix theory is applied to explore the magnetic sublevel population of the residual ions, as described in terms of alignment parameters. For the electron capture into the initially hydrogenlike U{sup 91+} and lithiumlike U{sup 89+} uranium projectiles, the alignment parameters are calculated, within the multiconfiguration Dirac-Fock approach, as a function of the collision energy and for different ionic states. From these calculations, we find that the many-electron interactions may result in a small enhancement of the alignment, and that this effect becomes more pronounced for highly excited levels.},
doi = {10.1103/PHYSREVA.73.0},
journal = {Physical Review. A},
number = 3,
volume = 73,
place = {United States},
year = {Wed Mar 15 00:00:00 EST 2006},
month = {Wed Mar 15 00:00:00 EST 2006}
}
  • The radiative electron capture into high-Z, few-electron ions is studies in the framework of the density matrix, based on Dirac's equation. In this formalism, all the properties of the photons and the (remaining) ions can be described, independent from their initial shell structure or polarization. Detailed computations have first been carried out for the total and angle-differential cross sections, following the capture of an electron into hydrogen-U{sup 91+} and lithiumlike U{sup 89+} ions. From these calculations, which were performed in two different approximations, it is shown that many-electron interactions affect the angular distribution at low projectile energies by about 5%.more » Apart from describing the (angular-dependent) capture cross sections, our formalism is also appropriate to explore the subsequent K{alpha},{beta} photon emission, if the electron is captured into an excited state of the ion, the polarization of the photons and ions as well as the interplay of the radiative with other, nonradiative capture processes in the future.« less
  • Electron-capture and deexcitation processes in collisions of excited Na{sup *}(3{ital p}) atoms with He{sup +} ions are studied in the energy range 0.1--7 keV/u by using the molecular-orbital-expansion method within the semiclassical framework. The integral alignment ({ital A}{sub 20}), alignment angle ({gamma}), and orientation ({ital O}) parameters of excited He(2 {sup 1}{ital P},2 {sup 3}{ital P}) orbitals resulting from electron capture are also determined. Furthermore, the effects of the initial alignment of the Na{sup *}(3{ital p}{sub {ital m}}) orbital on the cross sections, {ital O}, and {gamma} parameters are investigated. The present results show that the ratio of theoretical crossmore » sections for electron capture by the He{sup +} ion in collisions with the Na{sup *}(3{ital p}) atom and the ground state Na(3{ital s}) atom, respectively, is nearly equal to unity in the energy range studied here. The results also show that the {ital O} and {gamma} parameters are significantly different for the singlet and triplet manifolds, implying that different collision dynamics for He(2{ital p}) formation govern in each manifold. These parameters can be effectively controlled by adjusting the initial alignment of the Na{sup *}(3{ital p}) orbitals.« less
  • No abstract prepared.
  • The excited states of highly charged ions populated by charge transfer are frequently aligned. The alignment of each nl level often reflects the initial alignment due to the collision as well as the alignment of higher levels which cascade down to this level. We adapt the theory of alignment transfer and apply it to analyze the alignment of Lyman radiations following ion-atom collisions. The theory is illustrated using computed alignments of higher levels reported earlier and the results are compared with recent measurements.