Jet-cooled laser-induced dispersed fluorescence spectroscopy of ScN: Observation of a3Σ+ state

Laser-induced dispersed fluorescence spectra of ScN molecules, produced in a free-jet apparatus, have been studied. Low-energy first excited state, a3Σ+ predicted by ab initio calculations, has been observed for the first time. The relative term energies of the vibrational levels of the X1Σ+ ground, a3Σ+, and A1Σ+ states have been determined. The harmonic wavenumbers equal to 787.7(3) and 1044.8(1) cm−1, respectively for the X1Σ+ and A1Σ+ states and ΔG1/2 = 888(11) cm−1 for the a3Σ+ state have been measured. RKR potential energy curves of the X1Σ+ ground as well as a3Σ+ and A1Σ+ low-energy excited states have been constructed.