Extensions of the opacity project: Total electron-ion recombination rate coefficients for atoms and ions

Journal Article · Sat May 01 04:00:00 EDT 1993 · Bulletin of the American Physical Society

OSTI ID:281543

Pradhan, A K; Nahar, S N

As an extension of the Opacity Project (OP), total recombination rate coefficients of atoms and ions are being calculated employing a new computationally unified treatment which includes both the radiative and dielectronic recombinations (RR and DR) in an ab initio manner. In this new treatment contributions of RR and DR from all low n (n {<=} 10) states are obtained in a unified manner. Detailed photoionization cross sections that include autoionizing resonances are used for the contributions from low n states through the Milne relation. The contributions from the high n (10 {<=} n {<=} {infinity}) states, dominated by dielectronic recombination, are obtained using the precise theory of Bell and Seaton for DR that employs close-coupling wavefunctions and multichannel quantum defect theory. We calculate detailed and averaged DR collision strengths. Recombination rate coefficients for astrophysically important Silicon ions and improved results for Carbon sequence ions will be presented. The new rates are found to be significantly different from earlier rates obtained using separate treatments of RR and DR and in different approximations.

• OSTI ID: 281543
• Report Number(s): CONF-9305421--
• Journal Information: Bulletin of the American Physical Society, Journal Name: Bulletin of the American Physical Society Journal Issue: 3 Vol. 38; ISSN BAPSA6; ISSN 0003-0503
• Country of Publication: United States
• Language: English

Related Subjects

66 PHYSICS
CALCULATION METHODS
CARBON IONS
CROSS SECTIONS
ELECTRON-ION COLLISIONS
IONIZATION
RECOMBINATION
SILICON IONS