EXPERIMENTS WITH ALKALINE EARTH ATOMS EXCITED IN METASTABLE STATES - RADIATIVE LIFETIMES OF SOME HIGHLY EXCITED CA I LEVELS

An atomic beam source for atoms in metastable states is described. The source was used to produce metastable Ca and Sr atoms in the3P0,1,2 and1D2 and Mg atoms in the3P0,1,2 states. The population of these levels was high enough (about 30% of the atoms were in the3P levels and 3% in the1D2 level) so that zero field level crossing experiments could be performed at highly excited levels which were populated by an optical excitation starting from the metastable states. The lifetime results obtained for Ca are τ(4 s 4 d3D1)=(1.21±0.07)·10-8sec, τ(4 s 4f1F3)=(2.84±0.23)· 10-8sec, and τ(3 d 4 p1F3)=(6.15±0.62)·10-8 sec. The three lifetimes have been evaluated using the gJ values for LS-coupling. The quoted uncertainties include the errors by a possible deviation from LS-coupling. © 1969 Springer-Verlag.