Oscillator strengths and radiative transition rates for Kα lines in gold X-ray spectra: 1s-2p transitions

Abstract

Oscillator strengths (ƒ), line strengths (S) and radiative decay rates (A) are presented for all 1s-2p transitions in gold (Au) ions. X-ray emission from gold is extensively used, such as in fusion experiments, and in medical research for diagnostics and treatment. The Kα 1s-2p transitions in gold are found to be in the hard X-ray region of 66-73 keV (0.1888-0:1706 Å) and are limited to from hydrogen-like to fluorine-like ions as the 2p subshell is filled beyond fluorine. While there are two 1s-2p transitions (1s^2 S_1/2 - 2p^2 P^0_1/2 and 1s^2 S_1/2 - 2p^2 P^0_3/2) for hydrogen-like gold, Au^+78 , the number varies depending on the number of electrons in the 2p subshell before and after the transition. For example, there are 35 1s-2p transitions giving the same number of K_α lines for carbon-like Au, Au^+73 . The transitions can be of both types, dipole allowed and intercombination, and are in general strong, that is, A~10 =s. However, there are also weak transitions in the set. The present results are obtained from configuration interaction atomic structure calculations using the code SUPERSTRUCTURE which includes relativistic effects in Breit-Pauli approximation. The results have been benchmarked for a few ionic states with other detailed relativistic approaches, such as Dirac-Fock and coupled cluster. Comparisons with the very few transitions in the literature as well as those from other approaches indicate reasonable accuracy for the present results.