Raman spectra of GexAsySe100-x-y glasses

Raman spectra of GexAsySe100-x-y (0 < x < 30; 10 < y < 40) glasses have been studied at room temperature. Three sets of samples were investigated; it was revealed that they are qualitatively differing by shape of their spectra. The structure model was proposed for glasses of each set. The selection of the glasses on the sets with the same structure type can be made using the formal parameter - the mean coordination number <m> (the mean number of covalent bonds per atom): i) 2.1 < <m> < 2.51 (polymeric structure); ii) 2.51 < <m> < 2.78 (molecular-cluster structure); iii) 2.78 < <m> < 3 (network structure).