New ring-like models and ab initio DFT study of the medium-range structures, energy and electronic properties of GeSe₂ glass

Abstract

Ab initio DFT calculations were performed on Ge_nSe_m nanoclusters (n = 2, 3, 5, 6, 12; m = 6–9, 14, 16, 30) that represent the local structure of GeSe₂ glass and on some ‘defect’ Ge_nSe_m clusters that are thought to be related to the inhomogeneity of the structure at the nanoscale. The optimal geometries, total energies and their derivatives as well as the electronic properties of Ge_nSe_m nanoclusters were calculated using traditional DFT method. In addition, the TD-DFT method has been applied to calculate the electronic band gaps of the clusters. The calculated physico-chemical properties of Ge_nSe_m nanoclusters and their couplings with the local-and medium-range order structure formations in GeSe₂ glass are analysed and discussed.

Keywords:

• ab initio
• DFT
• GeSe₂ glass
• finite clusters

Acknowledgment

This work was performed within Ukrainian-Turkish collaboration in Science and Technology (Project Numbers M85-2010 and TUBITAK-109T643).