Identification of Raman Defect Lines as Signatures of Ring Structures in Vitreous Silica
1998; American Physical Society; Volume: 80; Issue: 23 Linguagem: Inglês
10.1103/physrevlett.80.5145
ISSN1092-0145
AutoresAlfredo Pasquarello, Roberto Car,
Tópico(s)Spectroscopy and Quantum Chemical Studies
ResumoBy analyzing the vibrational eigenmodes of a model structure obtained previously by quantum molecular dynamics, the two sharp features appearing in the Raman spectrum of vitreous silica could conclusively be assigned to three- and four-membered ring structures embedded in the network. The projections of the eigenmodes onto oxygen breathing motions in these rings yield well defined peaks at frequencies in striking correspondence to the positions of the Raman lines. The good agreement between calculated and measured shifts upon isotopic substitution further confirms this assignment.
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