RADIATIVE LIFETIMES OF THE LOWEST P-3(1) METASTABLE STATES OF CA AND SR

The lifetimes of the lowest P-3(1) states of Ca and Sr have been measu red in atomic beam experiments. These measurements have been made by o bserving the exponential decay of the fluorescence emitted from excite d states populated either by a discharge or a dye-laser pumping. In bo th cases, the velocity distributions of the radiating atoms were also measured by a time-of-flight technique. Our results show that the life time measurements using the discharge ex citation are hampered by a sy stematic error introduced probably by cascade transitions that repopul ate the upper energy levels of the transitions of interest. The radiat ive lifetimes of the 4s4p P-3(1) state of Ca and 5s5p P-3(1) state of Sr are determined to be 0.34 +/- 0.02 ms and 21.3 +/- 0.5 mu s, respec tively.