Time-resolved laser spectroscopy was used to measure radiative lifetimes of eight excited states of neutral sulfur in a laser-produced plasma. Excitation from the atomic ground state was performed with pulsed vacuumultraviolet ͑126-140 nm͒ radiation generated by resonant sum-difference four-wave mixing in krypton gas. The lifetimes of the 3 p 3 ns 3 S o ͑nϭ5-7͒ and 3p 3 nd 3 D o ͑nϭ4,5͒ states were measured and are presented together with data available from literature. Relativistic Hartree-Fock calculations of radiative lifetimes were also performed for states where experimental data were available. ͓S1050-2947͑97͒04403-X͔ PACS number͑s͒: 32.70. Cs, 42.62.Fi, 42.65.Ky

Natural radiative lifetimes of the states in the highly perturbed Sd' np P sequence in neutral gold, Au i, for n =6-9, as well as of four of the perturbing 5d 6s6p 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 +6p Pl/2) =6. 2(2) ns, &6p P3/2) =4. 7(2) ns,~7p Pl/2) =6. 4(7) ns,~7p P3/2) 5.3(7) ns,

Hyperfine structure (HFS) of La I are reported using Doppler-free intermodulated fluorescence, Doppler-limited laser-induced fluorescence and optogalvanic spectroscopy in a homemade hollow-cathode discharge tube. The A and B constants for the levels at 20197.34, 21447.86 cm-1 and A constants for the levels at 19379.40, 18156.97, 24910.38 and 24409.68 cm-1 are, to the authors' knowledge, reported for the first time. A linewidth less than 40 MHz and the different resolutions of fluorescence and optogalvanic spectroscopy are observed.

Oscillator strengths for the three 3s23p34s 3S1o-3s23p34p 3P0,1,2 transitions in neutral sulphur have been determined directly from lifetime measurements. Two-photon UV laser excitation and subsequent fluorescence detection have been used on atoms produced in a thermal sulphur beam or in a laser-driven plasma. A good agreement was found between data obtained in both schemes. The lifetime data obtained, τ(3P0) = 46.1(1.0) ns, τ(3P1) = 46.1(1.0) ns and τ(3P2) = 46.1(1.0) ns are compared with results of theoretical and experimental data from literature. The absorption oscillator strengths derived are f(3S1o-3P0) = 0.120(0.003), f(3S1o-3P1) = 0.360(0.008) and f(3S1o-3P2) = 0.600(0.013), respectively. For the next higher member of the series, 3s23p35p 3P1,2, a substantially longer lifetime, 188(13) ns, was obtained.

Time-resolved laser spectroscopy was used to measure natural radiative lifetimes of ten excited states of neutral bismuth. Four levels of the 6p ns P&/& sequence (n =7,8,9, 10) and the 6p 7s P3/2 5/2 and 6p nd D3/2. 5/2 (n =6,7) levels were investigated. The results are compared with previous data when possible. Revised absolute transition probabilities for 26 lines are given. Several levels required vacuum-ultraviolet (vuv) excitation, which was achieved by stimulated anti-Stokes Raman shifting of frequency-tripled dye-laser radiation in high-pressure H& gas.