Far-infrared spectra and bonding arrangement in Ge–As–S–Se glasses Original Research Article

Bulk glasses of formal chemical composition (GeSe2)x(As2S3)1−x were prepared by melting presynthesized As2S3 and elemental germanium and selenium. The values of hydrostatic density, optical gap, Urbach edge slope, refractive index, glass-transition and softening temperatures were determined. Measured far-infrared spectra were analysed in terms of two models, one in which bonds between cations (Ge and As) and anions (S, Se) form randomly and a second in which bond-strength between cations and anions is maximized in assembling the network. The analysis reveals preference for the second model, which suggests that in studied glasses the formation of Ge–S bonds is enhanced in the region 0