Oscillator strengths of sulphur 3s(2) 3p(3) 4s S-3(0)-3s(2) 3p(3) 4p P-3 transitions measured by time resolved two-photon laser spectroscopy

Oscillator strengths for the three 3s(2)3p(3)4s S-3(1)o-3s(2)3p(3)4p P-3(0,1,2) 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, tau(P-3(0)) = 46.1(1.0) ns, tau(P-3(1)) = 46.1(1.0) ns and tau(P-3(2)) = 46.1(1.0) ns are compared with results of theoretical and experimental data from literature. The absorption oscillator strengths derived are f(S-3(1)o-P-3(0)) = 0.120(0.003), f(S-3(1)o-P-3(1)) = 0.360(0.008) and f(S-3(1)o-P-3(2)) = 0.600(0.013), respectively. For the next higher member of the series, 3s(2)3p(3)5p P-3(1,2), a substantially longer Lifetime, 188(13) ns, was obtained.