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Brillouin scattering of vitreous silica under high pressure
Author(s) -
Rau S.,
Baeßler S.,
Kasper G.,
Weiss G.,
Hunklinger S.
Publication year - 1995
Publication title -
annalen der physik
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.009
H-Index - 68
eISSN - 1521-3889
pISSN - 0003-3804
DOI - 10.1002/andp.19955070202
Subject(s) - materials science , brillouin zone , brillouin scattering , absorption (acoustics) , distribution (mathematics) , asymmetry , coesite , optics , phase (matter) , phase boundary , hypersonic speed , scattering , rayleigh scattering , gaussian , spectral line , quartz , molecular physics , thermodynamics , physics , composite material , laser , geology , mathematical analysis , paleontology , mathematics , subduction , quantum mechanics , astronomy , eclogite , tectonics
The pressure dependence of Brillouin spectra of vitreous silica exhibits a maximum in the hypersonic absorption and a minimum in the sound velocity at about 2 GPa almost independent of temperature. The results are discussed on the basis of relaxing defects residing in double‐well potentials with a Gaussian distribution of barrier heights and a Lorentzian distribution in the asymmetry. Our analysis suggests that both the distribution functions are strongly changed at higher pressures. It is striking that a phase boundary between α‐quartz and coesite exists just at the pressure where absorption and sound velocity of vitreous silica pass their extremum. This might be a hint that a corresponding structural change also occurs in the glass.