Laser photoluminescence and photopredissociation of Rb2

Abstract

Laser‐photoluminescence studies of Rb₂ indicate that the C ¹Π_u state of the molecule is strongly predissociated. Both fixed frequency ion lasers and a tunable cw dye laser have used been to excite the photoluminescence at pressures from 1 to 100 torr of metal vapor contained in a heat‐pipe oven. The photoluminescence spectra show that the A ${}^1{\Sigma }_u^{+}$ and B ¹Π_u states also are populated following absorption by the C ¹Π_u state. Recombination collisions between Rb 5²P, formed in the predissociation of Rb₂, and Rb 5²S are proposed to account for the A→X and B→X emission. A strongly pressure dependent quasicontinuum emission is observed in the 540–610 nm region. This emission is attributed to transfer from the C ¹Π_u state into an unidentified state followed by transitions to high‐lying vibrational and continuum levels of the ground state.