Knowledge Bank

The emission spectrum of the $G4\Phi -X4\Phi$ transition of TiF has been observed in the $13500-16000cm-1$ 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 $CF4$ 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 $SFG$ using a pulsed supersonic jet source. Three groups of bands with high wavenumber sub-band heads at $14388cm-1,15033cm-1$, and $15576cm-1$ have been assigned as 0-1, 0-0, and 1-0 vibrational bands of the $G4\Phi -X4\Phi$ transition, respectively, Each vibrational band consists of four sub-bands assigned as $\mathrm{<mrow\; data-mjx-texclass="ORD">4</mrow>}\Phi 3/2,4\Phi 3/2,4\Phi 5/2,4\Phi 5/2,4\Phi 7/2-4\Phi 7/2$, and $\mathrm{<mrow\; data-mjx-texclass="ORD">4</mrow>}\Phi 9/2-4\Phi 9/2$. 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 $\mathrm{<mrow\; data-mjx-texclass="ORD">4</mrow>}\Phi$ 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.