Energy levels of small titanium oxide clusters obtained from SCF calculations

Abstract

The energy levels of small titanium oxide clusters [(Tioz)~, (Ti02)3, and (Ti02H)2] have been calculated using ab initio SCF methods. Both crystal and relaxed geometries have been considered. Systematic changes in the valencelevel structure resulting from geometry relaxation are found, which may be related to band-gap changes experimentally observed for small titanium oxide particles. In addition, a Ti-OH local surface state is found to be well described within a limited cluster model.

Electronic properties of the two rutiles TiO2 and VF2: A comparative study

“…1 for the LMTO-ASA calculations and 12 eV according to the all-electron Hartree-Fock calculation). This finding is supported by recent ab initio Hartree-Fock results on (TiO2)z and (TiO2)3 by Hagfeldt et al [35]. They found a width of the uppermost valence band somewhat over 5 eV, whereas the peak due to the 0 2s functions was found 25-30 eV below EF.…”

Spectroscopic and Theoretical Studies of Transition Metal Oxides and Dioxygen Complexes

“…All these M 2 O 4 clusters are characterized to have a 1 A g ground state with nonplanar C 2 h symmetry (Figure A). The clusters involve a rhombus M(μ-O) 2 M subunit and two terminal O atoms bending out of the M(μ-O)M plane in opposite directions. − ,,− A comparison between the experimental PES data and theoretical calculations verifies unequivocally that the Ti 2 O 4 − anion has a C 3 v structure. , The electronic structures of larger (TiO 2 ) n clusters have been the subject of several theoretical calculations. ,,− The recently reported photoelectron spectra of (TiO 2 ) n − ( n = 3−10) clusters reveal that the band gap is strongly size-dependent for n < 7, but it rapidly approaches the bulk limit at n = 7 and remains constant up to n = 10. All PES features are observed to be very broad, suggesting large geometry changes between the anions and the neutral clusters due to the localized nature of the extra electron in the anions.…”

“…The clusters involve a rhombus M(µ-O) 2 M subunit and two terminal O atoms bending out of the M(µ-O)M plane in opposite directions. [140][141][142][143][144]620,[622][623][624][625][626] A comparison between the experimental PES data and theoretical calculations verifies unequivocally that the Ti 2 O 4 anion has a C 3V structure. 135,149 The electronic structures of larger (TiO 2 ) n clusters have been the subject of several theoretical calculations.…”

TiO2Nanoparticles as Functional Building Blocks

“…Global minima structures for the discrete (TiO 2 ) n clusters were predicted as stable or low-energy metastable structures . Numerous experimental and theoretical studies investigated isolated titanium oxide clusters to correlate their structures and properties with those of the bulk phases. − The Ti n O 2 n and Ti n O 2 n +1 clusters were found to be the most stable neutral clusters, while Ti n O 2 n ‑1 and Ti n O 2 n ‑2 clusters were formed by fragmentation . Titanium oxide cluster cations, Ti n O 2 n ‑ m + ( n = 1–8; m = 0–4), were observed by sputtering titanium foil exposed to oxygen, and for n = 1–7 and m = 1–3 by sputtering titanium dioxide powder .…”