Ab initio and Raman study of medium range ordering in GeSe2 glass

High resolution Raman spectra of GeSe2 glass were measured and fitted using individual Gaussian components. The structural origin of the components were interpreted using the results of ab initio density functional theory calculations performed on GenSem nanoclusters (n = 2–6, 12; m = 6–9, 12, 14–16, 30) which represent the local structure of GeSe2 glass and on some “defect” GenSem clusters that are thought to be related to the inhomogeneity of the structure at the nanoscale. The calculated vibrational properties of GenSem nanoclusters and their couplings with the short- and medium-range order structure formations in GeSe2 glass are analyzed and discussed.