Determination of radiative lifetimes of neutral sulphur by time-resolved three-photon VUV laser spectroscopy.

Radiative lifetimes of the highly exited states s and d of neutral sulphur have been measured using time-resolved laser-induced fluorescence. The sulphur atoms were generated in a laser-produced plasma. The investigated states were populated through a two-step process involving a two-photon excitation to the lowest excited triplet state of even parity , followed by a one-photon excitation to the investigated state. We obtained ns and ns. These values are much longer than theoretically predicted ones and much shorter than those indirectely inferred from astronomical data. [ABSTRACT FROM AUTHOR]