Two-photon excitations of the Cs2 state: Assignment and analysis with the deformed ab initio potential

One color two-photon 3 3 Σ g + ← b 3 Π u ∼ A 1 Σ u + ← X 1 Σ g + transitions of Cs2 observed earlier [9] have been assigned: the upper state levels span the range of the vibrational and rotational quantum numbers v = 2 ∼ 9 and N = 25 ∼ 248 . The potential function of the 3 3 Σ g + state in a version of a deformed ab initio potential has been determined from the term values of these levels. The reliability of this potential is confirmed by simulations of the spectra of resolved fluorescence and by comparing with the Rydberg–Klein–Rees potential obtained from an alternative set of data in [13].