The FERRUM project: laboratory-measured transition probabilities for $ion{Cr}{ontsize{9pt}{11pt}selectfont{II}}$

摘要

Aims. We measure transition probabilities for Cr IItransitions from the z4HJ,z2DJ,y4FJ,and y4GJlevels in the energy range 63000 to68000cm-1. Methods. Radiative lifetimes were measured usingtime-resolved laser-induced fluorescence from a laser-produced plasma.In addition, branching fractions were determined fromintensity-calibrated spectra recorded with a UV Fourier transformspectrometer. The branching fractions and radiative lifetimes werecombined to yield accurate transition probabilities and oscillatorstrengths. Results. We present laboratory measured transitionprobabilities for 145 Cr II lines andradiative lifetimes for 14 Cr II levels.The laboratory-measured transition probabilities are compared to thevalues from semi-empirical calculations and laboratory measurements inthe literature. Key words: atomic data - line:identification - methods: laboratory - techniques: spectroscopic