New observation of Na2 43Σ+g state by pulsed perturbation facilitated optical-optical double resonance spectroscopy

Sixty-five new vibronic levels of the Na-2 4(3)Sigma(+)(g) state have been observed in the 33900-35200 cm(-1) energy 9region above the potential minimum of the ground state by pulsed perturbation facilitated optical-optical double resonance (PFOODR) fluorescence excitation spectroscopy. These new data fill the gap between the low-v levels mainly observed by continuous wave (CW)PFOODR spectroscopy and the high-v levels above the 3s+3d limit observed by pulsed PFOODR with predissociation detection. Molecular constants are fitted below potential shelf around the 3s+3d atomic limit with previously published data (mainly observed by CW PFOODR) and these new data. RKR potential curve has been calculated with the new constants. The constants are: T-e = 32127.090 cm(-1), w(e) = 121.4099(0.20720) cm(-1), B-e = 0.116287(0.0002300) cm(-1), R-e = 3.551 angstrom. An error of the RKR potential curve of J. Chem. Phys. 108, 7707 (1998) is corrected.