Radiative lifetime measurements in neutral lanthanum using time-resolved laser-induced fluorescence spectroscopy in supersonic free-jet

Abstract

Radiative lifetimes for 63 odd-parity energy levels of neutral lanthanum, in the range 13,260–30,965 cm−1, have been measured using time-resolved laser-induced fluorescence technique in a supersonic free-jet produced by laser vaporization of lanthanum metal. To the best of our knowledge, lifetimes for 45 levels are reported for the first time. The present lifetimes, with a few exceptions, are found to be in good agreement with the previously reported data. Lifetime values reported in this work fall in the range 9.5 to 313 ns and are accurate to ±10%. The levels belong to the 5d6s6p, 4f6s2, 6s26p, 5d26p, and 4f5d6s electronic configurations.