A comparative ab initio study to investigate the rich structural variety and electronic properties of GamTen (m = 1, 2 and n = 1–4) with analogous oxides, sulfides and selenides

Abstract

A series of gallium telluride, Ga_mTe_n (m = 1, 2 and n = 1–4), clusters has been examined using density functional theory (DFT), second-order Møller–Plesset perturbation theory (MP2) and the coupled cluster approach with single and double substitutions and a perturbative treatment of triple excitations [CCSD(T)]. The study unravels the question of whether neutral GaTe₂ is isostructural with BO₂ as proposed earlier by a previous experiment (Trans. Faraday Soc. 1968, 64, 2998). The results of gallium tellurides are compared with the oxygen, sulfur and selenium analogues. In most cases, the substitution of O/S/Se by Te atoms in the gallium clusters does not drastically affect the structural characteristics. The adiabatic electron affinities (AEAs) of Ga_mTe_n (m = 1, 2 and n = 1–4) clusters range from 1.33 to 3.46 eV at the CCSD(T)//B3LYP level. The AEAs of gallium tellurides are found to be independent on the electrophilicity of the clusters. Further, the adiabatic ionization potentials (AIPs) of the clusters are in good agreement with available experimental data. This research is expected to provide insight into the structural characteristics and electronic properties of gallium chalcogenides.