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Title: Interacting resonance effects along an isoelectronic sequence: Electron-impact excitation of Mg-like ions

Journal Article · · Physical Review A; (United States)
 [1];  [2]; ;  [3]
  1. Department of Physics and Applied Physics, University of Strathclyde, Glasgow G40NG (United Kingdom)
  2. Department of Physics, Rollins College, Winter Park, Florida 32789 (United States)
  3. Department of Physics, Auburn University, Auburn, Alabama 36849 (United States)

We have carried out a series of isolated-resonance and [ital R]-matrix close-coupling calculations for the electron-impact excitation of the 3[ital s][sup 2] [sup 1][ital S][r arrow]3[ital s]3[ital p] [sup 3][ital P] transition in the Mg-like ions Ar[sup 6+], Ti[sup 10+], Fe[sup 14+], and Se[sup 22+]. We obtain good agreement between the results of the two theoretical methods for three-state calculations, i.e., for the description of just a single Rydberg series of resonances. However, when two or more Rydberg series are present we observe large differences, due to interacting resonance effects, over a wide range of energies for all of the ions examined. For the case of Fe[sup 14+], we have continued the perturbative studies of interacting resonances of Griffin [ital et] [ital al]. [Phys. Rev. Lett. 72, 3491 (1994)] and also find the predominant effect to be due to direct configuration interaction between the resonant states rather than being due to their coupling through a common continuum. Our inclusion of these interacting resonance effects removes the major discrepancies between the perturbative and nonperturbative results for Fe[sup 14+] reported previously [Badnell [ital et] [ital al]., Phys. Rev. A 48, R2519 (1993)]. This is of importance for the study of indirect processes which are strongly radiation damped, for which the perturbative approach is widely used and the standard formulation of the close-coupling approximation is not applicable.

DOE Contract Number:
FG05-93ER54218; FG05-86ER53217
OSTI ID:
7270556
Journal Information:
Physical Review A; (United States), Vol. 50:2; ISSN 1050-2947
Country of Publication:
United States
Language:
English