U. Volz et al., IMPROVED RADIATIVE LIFETIMES OF HE-I 3S-3(1) AND 3D-3(J) BY BEAM-GAS-DYE-LASER SPECTROSCOPY, Journal of physics. B, Atomic molecular and optical physics, 28(4), 1995, pp. 579-589
The lifetimes of the 3(3)S(1) and 3(3)D(J) levels of the helium atom w
ere determined at improved precision by means of the cascade-free beam
-gas-dye-laser spectroscopy method. The influence of the divergence of
the helium-atom beam on the lifetime measurement was investigated in
detail and led to some substantial corrections. The resulting lifetime
s (including a correction for beam divergence) are 35.94 +/- 0.20 ns a
nd 14.12 +/- 0.06 ns, respectively, where the uncertainties quoted cor
respond to one standard deviation. The results are discussed in compar
ison with other experimental and theoretical work. The agreement betwe
en the present experiment and the results of the most refined theoreti
cal calculations is found to be excellent.