Molecular dynamics study of the vibrational pattern of ring structures in the Raman spectra of vitreous silica

Abstract

Raman scattering spectra of silica glass models were studied by means of molecular dynamics computer simulation. The study principally aimed at the inspection of the assignment of the defect bands of the Raman spectra of a-SiO₂ proposed by Galeener and co-workers (Galeener FL, Barrio RA, Martinez E, Elliott RJ. Phys. Rev. Lett. 1984; 53: 2429). The results of the study have shown that the D₂ peak at 606 cm^-1 can probably be related to the presence of three-membered rings in a-SiO₂, whereas the D₁ feature at 495 cm^-1 correlates with the presence of both three- and four-membered rings, and can therefore, be used for structural characterisation of silica glasses only with care

Probing vibrational modes in silica glass using inelastic neutron scattering with mass contrast

“…[7][8][9][10][11][12][13] Information about vibrations is available from the common techniques of IR and Raman spectroscopy, however, the visibility of modes is strongly dependent on complicated cross sections. An alternative experimental method is inelastic neutron scattering ͑INS͒, in which vibrations are probed by energy exchanges with thermal neutrons.…”

Recent advances in linear and non‐linear Raman spectroscopy. Part III

“…Raman scattering spectra of silica glass models were studied by To et al [177] by molecular dynamics computer simulation. This study aimed to assign the defect bands of the experimentally observed Raman spectra of a-SiO 2 .…”

Calculation of off‐resonance Raman scattering intensities with parametric models

“…[87,88] A recent study summarizes the noncompletely converging results of previous modeling analyses and suggests an interpretation suitable for a critical use of the experimental data for the structural characterization of the materials. [89] The main drawback of many previous studies was that the used classical approaches did not dispose on a reliable model for the calculation to the Raman intensity (Zotov et al [78] tried to calculate the Raman spectra of Na 2 Si 4 O 9 and SiO 2 glasses, but as the authors neglected the derivative of the transversal polarizability, they were not able to calculate intensities of the defect bands), while first-principles calculations, potentially capable of providing the most reliable results, were constrained to use small structural models, which could not yield a representative distribution of ring structures and thus led to large uncertainties on the calculated Raman intensities. The work in ref.…”

“…The work in ref. [89] used a silica glass model of 1536 atoms giving rise to a reasonable statistics of the rings as well as to a reliable calculation of the Raman spectrum with the parameters previously presented.…”

“…[56] had shown that the EOPs derived from molecular models led to reliable results for solids between 300 and 1000 cm −1 , this last study supports the validity of the results obtained in ref. [89] and the assignment of the D 2 band to the 3R subunits in silicate glasses.…”