## A Combined
Experimental and Theoretical Study of the Ti_{2} + N_{2}O Reaction

2014-01-23T00:00:00Z (GMT)
by

The reactivity of diatomic titanium
with nitrous oxide has been studied in solid neon. Two molecules with
the same Ti

_{2}–N_{2}O stoichiometry are identified from concentration, temperature, and irradiation effects. The more stable one is characterized by five fundamental vibrational transitions located below 1000 cm^{–1}, the high frequency one at 946 cm^{–1}corresponding to a pure TiO stretching mode. Its structure, a rhombus OTiNTiN with the extra O atom fixed on one Ti, is confirmed by quantum chemical calculations, at the CCSD(T) level, which predict a*C*structure in the singlet state with a Ti–O bond length close to 1.66 Å, two nonequivalent Ti–N distances close to 1.94 and 1.75 Å, and a OTiTi angle of 119.2°. The second Ti_{s}_{2}–N_{2}O molecule, only observed after annealing, is easily converted into the first one upon irradiation above 12 000 cm^{–1}and its kinetics of photoconversion allows vibrational transitions to be identified. The strongest one located at 2123.4 cm^{–1}characterizes an N–N stretching mode. Corresponding ab initio calculations complete this picture with details on the electronic structure and allow us to identify a most adequate density functional to describe the spectroscopic properties of the studied species in a simpler broken-symmetry open-shell DFT context. The theoretical results predict the existence of a metastable product OTi_{2}N_{2}and correctly account for the observed spectra of the various isotopic varieties.