The Rb2 31Π g state: Observation and analysis

The C(2)1Πu state in Rb2. Observation and deperturbation

We report a systematic study of the C(2)¹Π_uelectronic state in rubidium dimer, observed in polarization labelling spectroscopy experiment through the C ← X¹Σ_g⁺ transitions recorded under rotational resolution in two isotopologues ⁸⁵Rb₂ and ⁸⁵Rb⁸⁷Rb. Regularity of the vibrational progressions was distorted by numerous interactions with the surrounding 2¹Σ_u⁺, 2³Π_uand 3³Σ_u⁺states. Deperturbation was performed by coupled-channels analysis taking into account spin-orbit and rotational interactions. Potential energy curves and parameters describing the off-diagonal matrix elements were determined as functions of internuclear distance. About 3000 line frequencies from the present study are reproduced with a standard deviation of 0.07 cm^-1, in agreement with the experimental accuracy. Along with this, the model is consistent with all high resolution experimental data on the involved electronic states, available in the literature.