Mean lives andgfvalues in Ui

Abstract

Determinations of the mean lives of the 27887- and 16900-${\mathrm{cm}}^{-1\mathrm{}}$ levels in Ui have been made, each at a single vapor density, using electronic excitation and a method of delayed coincidence. The lifetime values were obtained by optically detecting the decays of the 3584.9- and 5915.4-Å resonance transitions, respectively. Using branching ratios obtained from known relative $f$ values, the averages of the measured lifetimes were corrected for imprisonment of the resonance radiation giving the following results: ${\tau }_0^{27887}=10.9\mathrm{}\pm 0.8$ ns and ${\tau }_0^{16900}=205\mathrm{}\pm 20$ ns. These mean lives were then used to place a system of relative $\mathrm{gf}$ values on two independent absolute scales, which were found to be in very close agreement. The lifetimes and $\mathrm{gf}$ values are presented in comparison with the experimental results of others.