A study of radiative and collisional decay of Pb atoms by time-resolved laser spectroscopy

Abstract

The 6p7s[Formula: see text] state of atomic Pb was populated by irradiation of Pb vapor by the frequency-doubled output of a pulsed nitrogen laser–pumped dye laser at the resonance wavelength λ = 2833 Å, and the resulting fluorescent decay was monitored using the method of delayed coincidences. A least squares fit to the observed time-decay spectrum yielded the decay constant and gave the radiative lifetime of the [Formula: see text] state, τ = 5.85 ± 0.20 ns. The dependence of the decay constant on buffer gas pressures was also investigated, yielding the total depopulation (quenching) cross sections Q = 0.31 ± 0.10 Å2 and 12.2 ± 1.0 Å2 for collisions with H2 and N2, respectively. An upper limit (Q < 0.2 Å2) for the He quenching cross section was also determined.