Atomic Data for SiI and SiII

We report accurate oscillator strengths of SiI and SiII lines, including lines from highly excited levels. We have performed large scale atomic structure calculations with the relativistic multiconfiguration Dirac-Hartree-Fock method using the GRASP2K package to determine log gf values of SiI and SiII lines, taking into account valence-valence and core-valence electron correlation.

In addition, we have derived oscillator strengths of SiI lines by combining the experimental branching fractions with radiative lifetimes from our calculations. The silicon plasma has been obtained from a hollow cathode discharge lamp and the intensity-calibrated high-resolution spectra have been recorded by a Fourier transform spectrometer. We provide an extensive set of accurate experimental and theoretical loggf values. 17 loggf values of SiI lines in the infrared were derived for the first time from experimental measurements.