DIRECT 2-COLOR PHOTOASSOCIATIVE IONIZATION IN A RUBIDIUM MAGNETOOPTICTRAP

We report the observation of direct, two-color photoassociative ioniza tion (PAI) in collisions between Rb-85 atoms optically cooled and conf ined 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 autoioniz ation, the Rb-2 intermediate photoionizes directly to Rb-2(+) in a fi xed optical field. These observations confirm PAI as a sensitive and b roadly applicable spectroscopic tool.