Far Infrared Spectra in (As2Se3)1-x(Sb2Se3)x Glasses

Abstract
Far infrared reflectivity spectra in (As2Se3)1-x (Sb2Se3) x (0 ≤x ≤0.4) glasses were studied in the spectral region 80–500 cm-1 at room temperature. Two-mode type behavior of the dominant modes observed in the spectra is shown to be characterized quite well by the local vibrations of As-Se3 and Sb-Se3 pyramidal molecular units. The oscillator strength for the Sb-Se3 unit is ca. 2.5 times larger than that for the As-Se3 unit. Predominance of heterobonding and valency conservation for the elements are deduced from this study. The effective charge e * for the dominant mode of the Sb-Se3 unit is calculated to be ca. 3.70e which is about 1.7 times larger than that of the As-Se3 unit. The stretching force constants K As-Se and K Sb-Se were calculated to be ∼1.77 and ∼1.65×105 dyns/cm, respectively.