PUZZLING DIATOMIC FEATURES SOLVED BY LASER-SPECTROSCOPY

Despite a resolution of 500 000, conventional (grating) spectroscopy failed in providing a satisfactory interpretation of the visible spectra of NbN and, above all, NbO. Laser spectroscopy techniques, from broad-band LIF up to sub-Doppler intermodulated LIF, were successfully used in order to understand these spectra. The main results are the observation of a case (a) coupling in the X4Σ- ground state of NbO and peculiar spin-uncoupling effects in the red system of NbN