STABLE STRUCTURES AND CHARACTERISTIC VIBRATIONAL SPECTRA OF TinOm(n = 2–4; m = 1–2n) CLUSTERS

Abstract

The energetically favorable structures and characteristic infrared (IR) and Raman peaks of Ti n O m(n = 2–4, m ≤ 2n) clusters are obtained in this work using a B3LYP/6-311G(d) method of density functional theory (DFT). The structures with m < 2n compose of Ti atoms of lower numbers of coordination with O atoms, providing many dangling bonds which considerably enhance the reactivity compared with its bulk counterpart. Two- and three-coordinated O atoms present for m/n ≤ 1.5, whereas two- and also single-coordinated O atoms are found for m/n > 1.5. The Ti n O m(n = 2–4, m < 2n) clusters show strong IR peaks in the range of 600–1100 cm-1 and strong Raman peaks in the region of 300–800 cm-1, whereas both the IR and Raman spectrum peaks of the Ti n O m(n = 2–4, m = 2n) clusters are in the region of 700–1100 cm-1. The main Raman peak of the Ti n O m(m ≠ 2n) clusters is at a frequency considerably lower than that of the IR spectrum. Our results can help understand the structure-property relationships of the Ti n O m clusters and provide their characteristic spectroscope features for further experimental identification.