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A Combined Experimental and Theoretical Study of the Ti2 + N2O Reaction
journal contribution
posted on 2014-01-23, 00:00 authored by A. Marzouk, H. Bolvin, P. Reinhardt, L. Manceron, J. P. Perchard, B. Tremblay, M. E. AlikhaniThe reactivity of diatomic titanium
with nitrous oxide has been studied in solid neon. Two molecules with
the same Ti2–N2O 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 Cs 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 Ti2–N2O 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 OTi2N2 and correctly account for the observed spectra of the
various isotopic varieties.