Mass-resolved resonance enhanced ionization study of complicated excited electronic states of Rb2 near 430 nm and their predissociation dynamics

High-lying electronic states of the rubidium dimer-Ab initio predictions and experimental observation of the 5(1)Σu(+) and 5(1)Πu states of Rb2 by polarization labelling spectroscopy

Two-colour polarization labelling experiments have been used to explore the excitation spectrum of the rubidium dimer in the region 25,500-27,000 cm(-1), probing two mutually interacting states, identified from ab initio calculations as the 5(1)Σu(+) and 5(1)Πu states whose atomic dissociation products are Rb(5s) + Rb(5d). Treating the rather irregular progressions observed in the excitation spectra as transitions to single states with (numerous) local perturbations, we propose spectroscopic parameters and potential energy curves to describe the investigated levels. Observations cover more than 20 vibrational levels in the inner minima of both the 5(1)Πu and 5(1)Σu(+) states. Analysis was guided by ab initio calculations performed to describe the (1,3)Λg,u electronic states of Rb2 up to the Rb(5s) + Rb(5f) atomic asymptote. The theoretical potential energy curves are given in ASCII format in an electronic supplement to this paper.

Unravelling complex spectra of a simple molecule: REMPI study of the 420 nm band system of KRb

Complex spectra of the KRb 420 nm system are analyzed by mass-resolved resonance enhanced two-photon ionization in a cold molecular beam. Vibronic structures of three singlet-singlet (4(1)Π, 7(1)Σ(+), and 5(1)Π←X(1)Σ(+)) transitions were identified for the first time. By comparing with highly accurate ab initio calculations, we assigned the singlet excited electronic states, and determined their electronic term values and vibrational constants. Weak singlet-triplet transitions were observed and identified as the 5(3)Π(0(+))←X(1)Σ(+) transitions by the homogeneous perturbation selection rule.

500 nm system of RbCs: assignments and intensity anomalies

We have investigated the RbCs 500 nm system by mass-resolved resonance enhanced two-photon ionization in a cold molecular beam. The 4 3Pi0 v' = 10-39, 4 3Pi1 v' = 14-28, and 6 1Sigma+ v' = 12-28 <-- X 1Sigma+ v'' = 0 transitions have been observed and assigned for the first time. The 4 3Pi0 v' <-- X 1Sigma+ v'' = 0 transitions abnormally show double maxima of the vibronic-band intensity distribution around v' = 22 and 38. The intensities of the transitions to the lower vibrational levels (4 3Pi0 v' = 10-32) are explained well by the direct transitions from the X 1Sigma+ v'' = 0 level following the Franck-Condon principle. The transitions to the higher vibrational levels (4 3Pi0 v' > or = 33) borrow intensities through the interaction with nearby 6 1Sigma+ perturber levels.