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(122) Production(s) de VACHER R.
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Raman spectroscopy of vitreous silica under rare gas compression 
Auteur(s): Weigel C., Foret M., Hehlen B. , Polian Alain, Vacher R., Ruffle B.
Conference: 3d Glass summit (Wuhan, CN, 2016-04-04)
Ref HAL: hal-01937850_v1
Exporter : BibTex | endNote
Résumé: We present accurate measurement of the VV- and VH-polarized Raman spectra of vitreous SiO2 pressurized in the range 0 – 8 GPa in argon or helium atmosphere by means of diamond anvil cell. A fine quantitative analysis of the behavior of the Raman modes in function of pressure is achieved with the help of an old central-force model by Sen and Thorpe describing the dynamics of covalently bonded networks. The model predicts the effect of changes in force constants and bond angles on the vibrational frequencies of the coupled SiO4 tetrahedral network. We show that the pressure shift of the Raman bands cannot be understood without encompassing the variations of both parameters. Investigating two different pressurizing fluids including He which is adsorbed into the silica network, allows revealing the role of each parameter in the compression mechanism of the glass.
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Elasticity of vitreous silica under fluid pressure
Auteur(s): Weigel C., Foret M., Kint M., Vacher R., Ruffle B., Polian Alain, Rouquette Jérome, Haines Julien, Coasne Benoit
Conference: Glass & Optical Materials Division Annual Meeting 2016 (Madison (WI), US, 2016-05-26)
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Polarized Raman spectroscopy of v-SiO2 under rare-gas compression
Auteur(s): Weigel C., Foret M., Hehlen B., Kint M., Clement S., Polian Alain, Vacher R., Ruffle B.
(Article) Publié:
Physical Review B, vol. 93 p.224303 (2016)
Ref HAL: hal-01337959_v1
DOI: 10.1103/PhysRevB.93.224303
WoS: 000378104200007
Exporter : BibTex | endNote
13 Citations
Résumé: High-pressure polarized Raman spectra of vitreous silica are measured up to 8 GPa in a diamond-anvil cell atroom temperature. The combined use of either a nonpenetrating pressurizing medium—argon—or a penetrating one—helium, allows one to separate density from stress effects on the Raman frequencies. In the framework of a simple central force model, the results emphasize the distinct role played by the shrinkage of the intertetrahedral angle Si-O-Si and the force-constant stiffening during the compression. The polarization analysis further reveals the existence of an additional isotropic component in the high-frequency wing of the boson peak. The pressure dependence of the genuine boson peak frequency is found to be much weaker than previously reported and even goes through a minimum around 2 GPa in remarkable coincidence with the anomalous compressibility maximum of silica.
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Raman spectroscopy of v-SiO2 under rare gas compression
Auteur(s): Weigel C., Hehlen B., Polian Alain, Ruffle B., Vacher R., Foret M.
Conference: Glass & Optical Materials Division Annual Meeting 2015 (Miami (FL), US, 2015-05-17)
Ref HAL: hal-01909062_v1
Exporter : BibTex | endNote
Résumé: We present accurate measurement of the VV- and VH-polarized Raman spectra of vitreous SiO2 pressurized in the range 0 – 8 GPa in argon or helium atmosphere by means of diamond anvil cell. A fine quantitative analysis of the behavior of the Raman modes in function of pressure is achieved with the help of an old central-force model by Sen and Thorpe describing the dynamics of covalently bonded networks. The model predicts the effect of changes in force constants and bond angles on the vibrational frequencies of the coupled SiO4 tetrahedral network. We show that the pressure shift of the Raman bands cannot be understood without encompassing the variations of both parameters. Investigating two different pressurizing fluids including He which is adsorbed into the silica network, allows revealing the role of each parameter in the compression mechanism of the glass.
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Elasticity of vitreous silica under fluid pressure
Auteur(s): Coasne Benoit, Weigel C., Polian Alain, Kint M., Rouquette Jérome, Haines Julien, Foret M., Vacher R., Ruffle B.
Conference: Glass & Optical Materials Division Annual Meeting 2015 (Miami (FL), US, 2015-05-17)
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