Updated potential energy function of the Rb2 a3Σu+ state in the attractive and repulsive regions determined from its joint analysis with the 23Π0g state

We report new experimental data for the Rb2 a3Σu+ and 23Π0g states obtained using the Perturbation Facilitated Infrared–Infrared Double Resonance (PFIIDR) technique. The results include ro-vibrational term values of the 23Π0g state and resolved fluorescence spectra of the 23Π0g→a3Σu+ transitions for a wide range of rotational and vibrational quantum numbers. An analysis of these data confirms the initial assignment of the transitions to the a3Σu+ state reported in our earlier work [B. Beser, V. B. Sovkov, J. Bai, E. H. Ahmed, C. C. Tsai, F. Xie, L. Li, V. S. Ivanov, and A. M. Lyyra, J. Chem. Phys. 131, 094505 (2009)]. The potential energy functions of the Rb2 a3Σu+ and 23Π0g states are derived from a simultaneous fit of the available experimental data. The improved potential function of the Rb2 a3Σu+ state spans both the attractive and repulsive regions starting with internuclear distance R ∼ 4.5 A.