Dielectronic recombination rate coefficients for highly ionized Ni-like atoms
- Racah Institute of Physics, The Hebrew University, 91904 Jerusalem (Israel)
- Nuclear Research Center-Negev, P.O. Box 9001, 84190 Beer-Sheva (Israel)
- Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94550 (United States)
{ital Ab} {ital initio} calculations of the total dielectronic recombination (DR) rate coefficients for ten ions along the NiI isoelectronic sequence in the ground state (Mo{sup 14+}, Ag{sup 19+}, Xe{sup 26+}, Pr{sup 31+}, Gd{sup 36+}, Dy{sup 38+}, Ta{sup 45+}, Au{sup 51+}, At{sup 57+}, and U{sup 64+}) have been performed using the HULLAC computer code package. Resonant and nonresonant stabilizing radiative transitions were included. Collisional transitions following electron capture were neglected. The present level-by-level calculations include the contributions of all the levels (over 17000) belonging to the following Cu-like inner-shell excited configurations: 3{ital d}{sup 9}4{ital ln}{prime}{ital l}{prime} ({ital n}{prime}{le}9), 3{ital p}{sup 5}3{ital d}{sup 10}4{ital ln}{prime}{ital l}` ({ital n}{prime}{le}5), and 3{ital s}3{ital p}{sup 6}3{ital d}{sup 10}4{ital ln}`{ital l}` ({ital n}`{le}5). The configuration complexes with a hole in the 3{ital p} inner shell contribute about 10{percent} to the total DR rate coefficients and the complexes with the hole in the 3{ital s} inner shell about 1%. The contributions of 3{ital d}{sup 9}4{ital ln}`{ital l}` for {ital n}`{approx_gt}9 were evaluated by extrapolation, applying an {ital n}{sup -3} scaling, which was checked for the specific Ta{sup 45+} case. It is shown that at electron temperatures higher than half the ionization energy {ital E{sub I}}(Cu) of the Cu-like ion, the Burgess-Merts (BM) semiempirical formula can provide DR results with an accuracy better than {+-}20% for the relatively heavy ions ({ital Z}{approx_gt}54), whereas for the lighter ions it leads to an underestimation of up to a factor 2 (for Mo). On the other hand, at low electron temperature [{ital kT{sub e}}{lt}0.3{ital E{sub I}}(Cu)] the BM approximation underestimates the DR rate coefficients by up to a few orders of magnitude and its temperature dependence is completely inadequate. {copyright} {ital 1996 The American Physical Society.}
- OSTI ID:
- 391669
- Journal Information:
- Physical Review A, Journal Name: Physical Review A Journal Issue: 4 Vol. 54; ISSN 1050-2947; ISSN PLRAAN
- Country of Publication:
- United States
- Language:
- English
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