Experimente mit Erdalkaliatomen in metastabilen Zuständen

An atomic beam source for atoms in metastable states is described. The source was used to produce metastable Ca and Sr atoms in the³ P _0,1,2 and¹ D ₂ and Mg atoms in the³ P _0,1,2 states. The population of these levels was high enough (about 30% of the atoms were in the³ P levels and 3% in the¹ D ₂ 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 areτ(4s 4d ³ D ₁)=(1.21±0.07)·10^?8sec,τ(4s 4f¹ F ₃)=(2.84±0.23)· 10^?8sec, andτ(3d 4p ¹ F ₃)=(6.15±0.62)·10^?8 sec. The three lifetimes have been evaluated using theg _J values forLS-coupling. The quoted uncertainties include the errors by a possible deviation fromLS-coupling.