Interference and diffuse continua in the Rb2 spectrum

Argon-ion laser-induced fluorescence measurements of rubidium vapour have been performed in order to study the 'quasi-continuum emission' of RB2 between 540 and 610 nm. By means of single longitudinal-mode excitations with 476.5 and 488 nm lines the authors found that this quasi-continuum band in the fluorescence spectrum consists of diffuse bands partly overlapped by the interference-type continuum, unresolved in previous experiments. This interference continuum appears at the longer wavelength end of the Stokes emission lines for a certain number of single longitudinal modes of 476.5 and 488 nm laser lines. The authors estimated the ground-state dissociation energy D0" (Rb2X1 Sigma g+)=4180+or-70 cm-1.