Atomic density and light intensity dependences of theRb2molecule formation rate constant in a magneto-optical trap

Abstract

In this paper, we report the measurement of molecular formation rate constant of ${\mathrm{Rb}}_{2}$ directly in a magneto-optical trap (MOT). The ground state molecules are detected by two-photon ionization, resonantly enhanced through the intermediate ${a}^{3}{\ensuremath{\Sigma}}_{u}^{+}\ensuremath{\rightarrow}{2}^{3}{\ensuremath{\Pi}}_{g}$ molecular band. We have measured the rate constant as a function of atomic density to conclude that the molecules ${\mathrm{Rb}}_{2}$ are formed in the MOT by a photoassociation process caused by the trapping laser beams. We also measured the rate constant as a function of the trapping laser intensity. The results here presented are of importance to future experiments involving trapping of cold molecules.