DIRECT 2-COLOR PHOTOASSOCIATIVE IONIZATION IN A RUBIDIUM MAGNETOOPTIC TRAP

We report the observation of direct, two-color photoassociative ionization (PAI) in collisions between Rb-85 atoms optically cooled and confined in a magneto-optical trap. We also measure the resulting R(2)(+) ion spectrum and compare it to earlier trap-loss fluoresecence spectra. Unlike PAI in Na, which ionizes principally by collisional autoionization, the Rb-2* intermediate photoionizes directly to Rb-2(+) in a fixed optical field. These observations confirm PAI as a sensitive and broadly applicable spectroscopic tool.