Structural model of thin (GeSe5)(1-x)Tl-x films

Far-infrared spectra of thin films from the Ge-Se-Tl system are investigate d. The results are interpreted in terms of the vibrations of the isolated m olecular units. The experimental results are compared with simulated spectr a based on the theory of strong oscillators. Six optical phonons are found using a spectral computer program ('Layers'). Raman spectra of thin films f rom the Ge-Se-Tl system are investigated. Modes associated with the Se-Se, Se-Ge and Se-TI bonds are obtained. On the basis of the determined bonds a structural model of the glasses is proposed.