Determination of radiative lifetimes of excited states in neutral gold using time-resolved vacuum-ultraviolet laser spectroscopy

Abstract

Natural radiative lifetimes of the states in the highly perturbed 5${\mathit{d}}^{10}$np $^{2}$P sequence in neutral gold, Au i, for n=6--9, as well as of four of the perturbing 5${\mathit{d}}^{9}$6s6p $^{2}$P states, have been measured. This was done by direct excitation from the ground state with short-pulse vacuum-ultraviolet laser light and time-resolved detection of the laser-induced fluorescence. We found the lifetimes to be \ensuremath{\tau}(6p $^{2}$${\mathit{P}}_{1/2}$)=6.2(2) ns, \ensuremath{\tau}(6p $^{2}$${\mathit{P}}_{3/2}$)=4.7(2) ns, \ensuremath{\tau}(7p $^{2}$${\mathit{P}}_{1/2}$)=6.4(7) ns, \ensuremath{\tau}(7p $^{2}$${\mathit{P}}_{3/2}$)=5.3(7) ns, \ensuremath{\tau}(8p $^{2}$${\mathit{P}}_{1/2}$)=63(3) ns, \ensuremath{\tau}(8p $^{2}$${\mathit{P}}_{3/2}$)=24(2) ns, \ensuremath{\tau}(9p $^{2}$${\mathit{P}}_{1/2}$)=28(2) ns, and \ensuremath{\tau}(9p $^{2}$${\mathit{P}}_{3/2}$)=75(4) ns. For the perturbing states (two states of each term have been observed) we found \ensuremath{\tau}${(}^{2}$${\mathit{P}}_{1/2}$, 60 983.05 ${\mathrm{cm}}^{\mathrm{\ensuremath{-}}1}$)=17.5(10) ns, \ensuremath{\tau}${(}^{2}$${\mathit{P}}_{1/2}$, 62 540.65 ${\mathrm{cm}}^{\mathrm{\ensuremath{-}}1}$)=6.7(7) ns, \ensuremath{\tau}${(}^{2}$${\mathit{P}}_{3/2}$, 58 826.30 ${\mathrm{cm}}^{\mathrm{\ensuremath{-}}1}$)=2.1(15) ns, and \ensuremath{\tau}${(}^{2}$${\mathit{P}}_{3/2}$, 63 005.62 ${\mathrm{cm}}^{\mathrm{\ensuremath{-}}1}$)=2.7(15) ns. Furthermore, we have investigated the hyperfine structure of the 6p $^{2}$${\mathit{P}}_{3/2}$ state.