OSCILLATOR STRENGTHS FOR DIPOLE-ALLOWED FINE-STRUCTURE TRANSITIONS IN Si II

✍ Scribed by SULTANA N NAHAR

• Publisher: Elsevier Science
• Year: 1998
• Tongue: English
• Weight: 982 KB
• Volume: 68
• Category: Article
• ISSN: 0092-640X
• DOI: 10.1006/adnd.1997.0760

✦ Synopsis

An extensive dataset of oscillator strengths, line strengths, and Einstein A-coefficients has been calculated for a large number of dipole-allowed (DS Å 0) fine-structure transitions in Si II. The line strengths in LS coupling are obtained in an ab initio manner in the close-coupling approximation employing the R-matrix method. The fine-structure components are obtained through algebraic transformations of the LS multiplets. Observed spectroscopic energies are employed whenever available. A 12-state eigenfunction expansion of the core ion, Si III, is employed for the present calculations. This work presents the oscillator strengths of 1122 fine-structure transitions in Si II corresponding to 390 LS multiplets and provides a reasonably complete set of radiative transitions for this astrophysically important ion for the first time. Present results are of comparable accuracy to previous detailed calculations obtained for a small number of transitions and are in reasonably good agreement with the measured oscillator strengths and lifetimes.