Relativistic fine structure oscillator strengths for Li-like ions: C IV - Si XII, S XIV, Ar XVI, Ca XVIII, Ti XX, Cr XXII, and Ni XXVI

Department of Astronomy, The Ohio State University, Columbus, OH 43210, USA

Corresponding author: nahar@astronomy.ohio-state.edu

Received: 18 February 2002
Accepted: 30 April 2002

Abstract

Ab initio calculations including relativistic effects in the Breit-Pauli R-matrix (BPRM) method are reported for fine structure energy levels and oscillator strengths upto and for 15 Li-like ions: C IV, N V, O VI, F VII, Ne VIII, Na IX, Mg X, Al XI, Si XII, S XIV, Ar XVI, Ca XIII, Ti XX, Cr XXII, and Ni XXVI. About one hundred bound fine structure energy levels of total angular momenta, of even and odd parities, total orbital angular momentum, and spin multiplicity (2S + 1) = 2, 4 are obtained for each ion. The levels provide almost 900 allowed bound-bound transitions. The BPRM method enables consideration of large set of transitions with uniform accuracy compared to the best available theoretical methods. The CC eigenfunction expansion for each ion includes the lowest 17 fine structure energy levels of the core configurations , , , , , and . The calculated energies of the ions agree with the measured values to within 1% for most levels. The transition probabilities show good agreement with the best available calculated values. The results provide the largest sets of energy levels and transition rates for the ions and are expected to be useful in the analysis of X-ray and EUV spectra from astrophysical sources.