Using perturbation facilitated infrared-infrared double resonance excitation of the (85)Rb(2) molecule, we have observed spectrally resolved fluorescence to the a (3)Sigma(u)(+) state. We have analyzed the rovibrational energy level structure of the (85)Rb(2) a (3)Sigma(u)(+) state and derived a multiparameter Morse Long Range (MLR) potential and molecular constants for this state, which can be used to predict term values without needing to solve the radial Schrödinger equation.

The lowest electronically excited states of Na2 are of interest as intermediaries in the excitation of higher states and in the development of methods for producing cold molecules. We have compiled previously obtained spectroscopic data on the A 1Sigmau+ and b 3Piu states of Na2 from about 20 sources, both published and unpublished, together with new sub-Doppler linewidth measurements of about 15,000 A<--X transitions using polarization spectroscopy. We also present new ab initio results for the diagonal and off-diagonal spin-orbit functions. The discrete variable representation is used in conjunction with Hund's case a potentials plus spin-orbit effects to model data extending from v=0 to very close to the 3 2S+3 2P12 limit. Empirical estimates of the spin-orbit functions agree well with the ab initio functions for the accessible values of R. The potential function for the A state includes an exchange potential for S+P atoms, with a fitted coefficient somewhat larger than the predicted value. Observed and calculated term values are presented in an auxiliary (EPAPS) file as a database for future studies on Na2.