VIBRATIONAL NUMBERING AND POTENTIAL OF THE C(3)SIGMA(+) STATE OF NAK DETERMINED FROM THE C(3)SIGMA(+)-]A(3)SIGMA(+) TRANSITION

We report the observation of the c 3Σ+ → a 3Σ+ emission in NaK following excitation of single rovibronic levels in the c 3Σ+ state. The dispersed fluorescence displays both diffuse and discrete features. The characteristic reflection structure of the bound-free spectra permits a direct, unambiguous assignment of the vibrational numbering in the c 3Σ+ state: The v = 20 level is the first vibrational level of c 3Σ+ lying above v = 0 in the B 1Π state. The c 3Σ+ state potential curve is determined from bound-free parts of the observed spectra with the inversion procedure of LeRoy et al. [J. Chem. Phys. 89, 4564 (1988)]; its most important parameters are Te = 15 857±15 cm-1 and Re = 0.445±0.001 nm. © 1995 American Institute of Physics.