LASER AND FOURIER TRANSFORM EMISSION SPECTROSCOPY OF THE $G^{4}\Phi -X^{4}\Phi$ SYSTEM OF TITANIUM MONOFLUORIDE.

Abstract

The emission spectrum of the $G^{4}\Phi - X^{4}\Phi$ transition of TiF has been observed in the $13500 - 16000\;cm^{-1}$ region using a Fourier transform spectrometer (FTS), as well as by laser excitation spectroscopy. In the FTS experiments, the bands were excited in a carbon tube furnace by the reaction of titanium metal vapor with $CF_{4}$ at a temperature of about $2300^\circ C$. In the laser experiments, the TiF molecules were produced by laser vaporization of a Ti rod followed by reaction with $SF_{G}$ using a pulsed supersonic jet source. Three groups of bands with high wavenumber sub-band heads at $14388\;cm^{-1},\;15033\;cm^{-1}$, and $15576\;cm^{-1}$ have been assigned as 0-1, 0-0, and 1-0 vibrational bands of the $G^{4}\Phi - X^{4}\Phi$ transition, respectively, Each vibrational band consists of four sub-bands assigned as $^{4}\Phi_{3/2}, ^{4}\Phi_{3/2}, ^{4}\Phi_{5/2}, ^{4}\Phi_{5/2}, ^{4}\Phi_{7/2} - ^{4}\Phi_{7/2}$, and $^{4}\Phi_{9/2} - ^{4}\Phi_{9/2}$. A rotational analysis has been performed and molecular constants for the ground and excited states have been extracted using the combined FTS and laser excitation measurements. The assignment of a $^{4}\Phi$ state as the lower state is consistent with recent theoretical predictions and with expectations based on the spectrum of TiH. The similarity between the electronic states of TiF, TiH, and $Ti^{+}$ will be discussed.