ANASTASIA DROZDOVA, Department of Chemistry, Moscow State University, 119991 Moscow, Russia ; ABDUL-RAHMAN ALLOUCHE, GHASSAN WANNOUS, PATRICK CROZET AND AMANDA J. ROSS, Institut Lumière Matière, Université Lyon 1 & CNRS UMR5306, Université de Lyon, France.
We have performed a series of optical-optical double resonance experiments with one or two cw Ti:sapphire lasers, to excite the 2~1 g state of Rb2, recording infrared fluorescence from 2~1 g on a Fourier transform spectrometer. Fluorescence from the lower vibrational levels of 2~1 g (Te = 22069.56 cm-1) is dominated by transitions to the B 1 u state studied by Amiot and Vergès. Vibrational and rotational relaxation from laser-pumped levels v' < 15 now give a rather complete description around the potential minimum of the 2~1 g state, completing the observations for 6 \leq~v~\leq 50 reported by Han et al last year. Fluorescence from v' > 35, occurs also to the 0+ components of the A~1 u+ b~3 u complex. Fitting all available 2~1 g B~1 u data for 85Rb2 and 85Rb87Rb (several thousand transitions) has also given an improved description of the bottom of the B 1 u state potential well. The 2~1 g state correlates at long-range with Rb 5s + Rb 4d 2D3/2 atoms, giving a dissociation energy of 1279.6 cm-1. Most new data lie below v = 45, 250 cm-1 below this dissociation threshold.