Absolute oscillator strengths of CrII-lines from combined phase shift and emission measurements

Abstract

Oscillator strengths of lines of singly ionized chromium have been obtained by a combination of emission and spectro-interferometric measurements. A hollow cathode is used as a light source for the emission measurements, where relative oscillator strenghts of lines with the upper level in common are determined by measuring branching ratios. The determination of relative oscillator strenghts of lines having the lower level in common is based on a phase shift method, which employs a Fourier analysis of the spectral interferograms. A modified wallstabilized arc serves as the light source here. Large sets of relative oscillator strenghts are obtained by linking the results of the two types of measurements. With known lifetimes the relative f-values are connected to an absolute scale where the overall uncertainty is between 10 and 30%.