Radiative Lifetimes Of The 6s8p P-1(1) And Near-Resonant States In Barium

Radiative lifetimes of eight states in Ba are measured in a metal vapor oven via pulsed laser excitation with time- and wavelength-resolved fluorescence detection. The lifetimes found for these states are tau(6s8p P-1(1))=136+/-2 ns, tau(6p2 1D2)=12+/-1 ns, tau(6p2 P-3(2))=7.3+/-0.4 ns, T(6s7d 3D3)=30+/-1 ns, tau(6s7d 3D2)=39+/-1.8 ns, tau(6s7d3D1)=39+/-1.2 ns, tau(5d6d 3G3)=22+/-1.2 ns, and tau(5d6d 3D1)=23+/-1.8 ns. The 6s8p P-1(1) state is excited by a pulsed, frequency-doubled dye laser at 278.5 nm, and its lifetime is determined from the exponential decay of 408.2-nm emission on the 6s 8p P-1(1) --> 6s 5d 1D2 transition. With He buffer gas in the cell at densities of around 6 X 10(14) cm-3, population is transferred to the other seven states lying within 550 cm-1 of the 6s8p state. Radiative lifetimes of these collisionally populated states are determined from the exponential rise times of their wavelength-resolved emissions.