Photoelectron spectroscopy and density functional theory study of TiAlO y- (y=1-3) and TiAl_2 Oy- (y=2-3) clusters

摘要

Small titanium-aluminum oxide clusters, TiAlO y- (y=1-3) and TiAl _2 Oy- (y=2-3), were studied by using anion photoelectron spectroscopy. The adiabatic detachment energies of TiAlO y- (y=1-3) were estimated to be 1.11±0.05, 1.70±0.08, and 2.47±0.08 eV based on their photoelectron spectra; those of TiAl_2 O2- and TiAl_2 O_3~- were estimated to be 1.17±0.08 and 2.2±0.1 eV, respectively. The structures of these clusters were determined by comparison of density functional calculations with the experimental results. The structure of TiAlO- is nearly linear with the O atom in the middle. That of TiAlO 2- is a kite-shaped structure. TiAlO 3- has a kite-shaped TiAlO_2 unit with the third O atom attaching to the Ti atom. TiAl_2 O_2~- has two nearly degenerate Al-O-Ti-O-Al chain structures that can be considered as cis and trans forms. TiAl_2 O3- has two low-lying isomers, kite structure and book structure. The structures of these clusters indicate that the Ti atom tends to bind to more O atoms.