Bound-state transitions in few-electron, heavy ions following radiative electron capture are studied within the framework of the density matrix theory and the multiconfiguration Dirac-Fock approach. Special attention is paid to the K α1 (1 s1/2 2 p3/2 1.3PJ=1,2→1s21/2 1SJ=0) radiative decay of heliumlike uranium U90+ projectiles. This decay has recently been observed at the GSI facility in Darmstadt, giving rise to a surprisingly isotropic angular distribution, which is inconsistent with previous experiments and calculations based on a "one-particle" model. We show that the unexpected isotropy essentially results from the mutual cancellation of the angular distributions of the 1P11S0 electric dipole and 3P21S0 magnetic quadrupole transitions, both of which contribute to the K α1 radiation. Detailed computations on the anisotropy of the K α1 radiation have been carried out for a wide range of projectile energies and are compared to available experimental data.



Keywords and Phrases

Anisotropy; Computation Theory; Electrons; Magnetic Properties; Uranium; Heliumlike Ions; Isotropic Angular Distribution; Isotropy; Relativistic Collisions; Heavy Ions

International Standard Serial Number (ISSN)


Document Type

Article - Journal

Document Version

Final Version

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© 2006 American Physical Society (APS), All rights reserved.

Publication Date

01 Nov 2006

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Physics Commons