LASER SPECTROSCOPY OF TIO - ACCURATE TERM ENERGIES FOR THE SINGLET-STATES AND LIGAND-FIELD ASSIGNMENT OF STATES IN THE RANGE 0-EV TO 4-EV

The wavelength-resolved fluorescence excitation technique has been use d to record the (2,0) band of the C-3 Delta(3)-alpha(1) Delta transiti on, and the (2,3) and (2,4) bands of the C-3 Delta(3)-X(3) Delta(3) el ectronic transition of TiO at a resolution of 0.03 cm(-1). These data were combined with a previous high-resolution analysis of the C-3 Delt a-X(3) Delta system (T. Gustavsson, C. Amiot, and J. Verges, J. Mel. S pectrosc. 145, 56-65, 1991) to obtain accurate term energies for the s inglet states of TiO. The term energy for the first excited alpha(1) D elta state is T-0(alpha(1) Delta) = 3444.367 +/- 0.020 cm(-1). This va lue differs significantly from the previously derived value of T-0(alp ha(1) Delta) = 3448.33 +/- 0.04 cm(-1) (A. I. Kobylyanskii, A. N. Kuli kov, and L. V. Gurvich, Opt. Spectrosc. 54, 254-255, 1983). Ligand fie ld theory models were used to analyze the electronic structures of TiO , TiS, and TiCl+. (C) 1995 Academic Press, Inc.