HIGH RESOLUTION LASER SPECTROSCOPY OF NIOBIUM NITRIDE

Author Institution: Department of chemistry, 2036 Main Mall, University of British Columbia; Institut f\""{u}r Molek\""{u}lphysik, Frele Universit\""{a}t BerlinThe taser induced fluorescence spectrum of gas phase niobium nitride (NbN) in the region 5700 \AA to 6300 \AA has been recorded with Doppler limited resolution, and also with sub-Doppler resolution by the intermodulated fluorescence technique for selected regions. The spectrum includes two triplet systems, the $3\phi - 3\Delta$ and the $^{3}\Pi - ^{3}\Delta$. Both systems show very impressive hyperfine splittings due to the interaction between the 9/2 Nb nuclear spin and a metal-centered unpaired electron. For the $^{3}\Pi - ^{3}\Delta$ system, it has been found that the middle $^{3} \pi_{1} - ^{3}\Delta_{2}$ sub-band is shifted from its regular middle position to the lowest position, presumably due to an interaction between the $^{3}\pi_{1}$ state and another close lying electronic state. The assignment of the electronic states was aided by the study of hyperfine splitting patterns and also by relative intensities of rotational lines obtained with the wavelength resolved fluorescence technique. Wavelength resolved fluorescence has also shown the existence of other low lying states and the possibility that the real electronic ground state lies still below the $^{3} \Delta$ state