old_07_lifetime
Lifetime Measurements and Absolute Oscillator Strengths for Single Ionized Thorium (ThII)
H. Simonsen, T. Worm, P. Jessen, and O. Poulen
Institute of Physics, University of Aarhus, DK-8000 Aarhus C, Denmark
Using collinear fast beam cw dye laser modulation spectroscopy accurate lifetimes in ThII have been measured. Together with known branching ratios these lifetimes have allowed the determination of absolute oscillator strengths for ThII. This element is of astrophysical interest as a chronometer for stellar and galaxy evolution, with oscillator strengths playing an important role in synthesis of stellar spectral data.