LASER ABSORPTION SPECTROSCOPY OF $TiCl^{+}$ : ANALYSIS OF THE [17.9]$^{3}\Delta-X^{3}\Phi(0, 0)$ Band

$^{a}$W. J. Balfour and K. S. Chandrasekhar, J. Mol. Spectrose. 139, 245-252 (1990). $^{b}$ L. A. Kaledin, J. E. McCord, and M. C. Heaven, J. Mol. Spectrose. 173, 499-509 (1995).Author Institution: Department of Chemistry, Emory UniversityThe laser absorption spectrum of the $TiCl^{+}$ molecular ion was observed for the first time in a hollow cathode discharge. The discharge was driven at 25 KHz at powers in the range of 80- 100 W. Peak currents of 0.5 A occured during the conducting half-cycles. Flowing samples of $TiCl_{4}$ in Ar were discharged. 235 lines of the $^{48}Ti^{35}Cl^{+}[17.9]^{3}\Delta-X^{3}\Phi(0, 0)$ band and 122 lines of the $^{48}Ti^{37}Cl^{-}[17.9]^{3}\Delta-X^{3}\Phi(0, 0)$ band were recorded at resolution $0.02 cm^{-1}$. This band system was observed previously $^{a}$ in the emission spectrum of $TiCl^{+}$ but the electronic assignments for the lower and upper states of the transition are revised here. Rotational constants (in $cm^{-1}$) and internuclear distances $r_{o}$ (in nm) for the [17.9]$^{3}\Delta$ (v=0) and $X^{3}\Phi$ (v=0) states of $^{48}Ti^{35}Cl^{-}$ and $^{48}Ti^{37}Cl^{+}$ are respectively:$$B^{\prime}_{0}=0.178692(16), r^{\prime}_{0}=0.2160(1),B^{\prime\prime}_{0}=0.174212(16), r^{\prime\prime}_{0}=0.2188(1)$$$$B^{\prime}_{0}=0.173076(18), r^{\prime}_{0}=0.2160(1),B^{\prime\prime}_{0}=0.168742(18), r^{\prime\prime}_{0}=0.2188(1)$$ These results are in excellent agreement with the predictions based on the ligand field theory $models^{b}$. The symmetry for the ground state of the $TiCl^{+}$ molecular ion is determined to be $X^{3}\Phi$. Work supported by AFOSR under grant F19628-90-C-025