REACTIONS OF LASER-ABLATED TI ATOMS WITH HYDROGEN DURING CONDENSATION IN EXCESS ARGON - INFRARED-SPECTRA OF THE TIH, TIH2, TIH3, AND TIH4 MOLECULES

Reactions of pulsed-laser evaporated Ti atoms with H-2 in a condensing argon stream gave TiH, TiH2, TiH3, TiH4, and polymeric species. The main difference between pulsed laser and thermal evaporation Ti atom reactions is the observation of all four products directly after sample deposition and the appearance of the new TiH and TiH3 radicals with laser evaporation. The assignments were based on concentration dependence and isotopic substitution and were confirmed by SCF frequency calculations. The stable D-3h titanium trihydride radical was identified from agreement between calculated and observed values for the eight active stretching frequencies for TiH3, TiH2D, TiHD2, and TiD3. Both experimental and theoretical results show that H atoms play an important role in the reaction mechanism.