LASER-ABSORPTION SPECTROSCOPY OF TICL- ANALYSIS OF THE [17.9](3)DELTA-X-3-PHI(0,0) BAND( )

The laser absorption spectrum of the TiCl+ molecular ion has been obse rved for the first time in a hollow cathode discharge. The discharge w as driven at 25 kHz at powers in the 80-100 W range. Flowing samples o f TiCl4 in Ar were discharged. A total of 235 lines of the (TiCl+)-Ti- 48-Cl-35 [17.9] (3) Delta-X-3 Phi (0,0) band and 122 lines of the (TiC l+)-Ti-48-Cl-37 [17.9] 3 Delta-X-3 Phi (0,0) band were recorded at res olution 0.02 cm(-1). Rotational constants for the [17.9](3) Delta (ups ilon = 0) and X-3 Phi, (upsilon = 0) states of the (TiCl+)-Ti-48-Cl-35 and (TiCl+)-Ti-48-Cl-37 isotopomers are reported. This band system wa s observed previously in the emission spectrum of TiCl+ (W. J. Balfour and K. S. Chandrasekhar, 1990, J. Mel. Spectrosc. 139, 245-252) but t he electronic assignments for the lower and upper states of the transi tion are revised here. The present experimental results are in excelle nt agreement with predictions based on ligand field theory models (L. A. Kaledin, J. E. McCord, and M. C. Heaven, 1995, J. Mol. Spectrosc. 1 73, 499-509). The symmetry for the ground state of the TiCl+ molecular ion was determined to be X-3 Phi. (C) 1997 Academic Press.