Hyper-Raman scattering analysis of the vibrations in vitreous boron oxide (2007)
Simon, G., Hehlen, B., Vacher, R., Courtens, E.
Hyper-Raman scattering has been measured on vitreous boron oxide, $v-$B$_2$O$_3$. This spectroscopy, complemented with Raman scattering and infrared absorption, reveals the full set of vibrations...
The Boson Peak and its Relation with Acoustic Attenuation in Glasses (2007)
Rufflé, B., Parshin, D. A., Courtens, E., Vacher, R.
Experimental results on the density of states and on the acoustic modes of glasses in the THz region are compared to the predictions of two categories of models. A recent one, solely based on an...
Ruffle, B., Foret, M., Courtens, E., Vacher, R., Monaco, G.
The linewidth of longitudinal acoustic waves in densified silica glass is obtained by inelastic x-ray scattering. It increases with a high power alpha of the frequency up to a crossover where the...
Rufflé, B., Guimbretière, G., Courtens, E., Vacher, R., Monaco, G.
The dynamic structure factor of lithium-diborate glass has been measured at several values of the momentum transfer $Q$ using high resolution inelastic x-ray scattering. Much attention has been...
Hyper-Raman scattering from vitreous boron oxide: coherent enhancement of the boson peak (2005)
Simon, G., Hehlen, B., Courtens, E., Longueteau, E., Vacher, R.
Hyper-Raman scattering spectra of vitreous B$_2$O$_3$ are reported and compared to Raman scattering results. The main features are indexed in terms of vibrations of structural units. Particular...
Glass-specific behavior in the damping of acoustic-like vibrations (2005)
Rufflé, B., Guimbretière, G., Courtens, E., Vacher, R., Monaco, G.
High frequency sound is observed in lithium diborate glass, Li$_2$O--2B$_2$O$_3$, using Brillouin scattering of light and x-rays. The sound attenuation exhibits a non-trivial dependence on the...
Rat, E., Foret, M., Massiera, G., Vialla, R., Arai, M., Vacher, R., ...
This series discusses the origin of sound damping and dispersion in glasses. In particular, we address the relative importance of anharmonicity versus thermally activated relaxation. In this first...
Anharmonic vs. relaxational sound damping in glasses: II. Vitreous silica (2005)
Vacher, R., Courtens, E., Foret, M.
The temperature dependence of the frequency dispersion in the sound velocity and damping of vitreous silica is reanalyzed. Thermally activated relaxation accounts for the sound attenuation observed...
Courtens, E., Foret, M., Hehlen, B., Ruffle, B., Vacher, R.
Spectroscopic results on low frequency excitations of densified silica are presented and related to characteristic thermal properties of glasses. The end of the longitudinal acoustic branch is marked...
Ruffle, B., Foret, M., Courtens, E., Vacher, R., Monaco, G.
The linewidth of longitudinal acoustic waves in densified silica glass is obtained by inelastic x-ray scattering. It increases with a high power alpha of the frequency up to a crossover where the...
From colloidal-silica sols to aerogels and xerogels (1992)
Foret, M., Chougrani, A., Vacher, R., Pelous, J.
By destabilization of quasi-monodisperse silica sols, fractal clusters can be obtained. Solvent evacuation gives a porous solid with fractal structure. Structural investigations of these colloidal...
Bonnet, Jp, Vacher, R, Pelous, J, Laermans, C
The acoustic properties of neutron-irradiated quartz have been investigated at ultrasonic frequencies by the pulse-echo method, and at hypersonic frequencies by Brillouin scattering. Four samples...
From colloidal-silica sols to aerogels and xerogels (1992)
Foret, M., Chougrani, A., Vacher, R., Pelous, J.
By destabilization of quasi-monodisperse silica sols, fractal clusters can be obtained. Solvent evacuation gives a porous solid with fractal structure. Structural investigations of these colloidal...
From colloidal-silica sols to aerogels and xerogels (1992)
Foret, M., Chougrani, A., Vacher, R., Pelous, J.
By destabilization of quasi-monodisperse silica sols, fractal clusters can be obtained. Solvent evacuation gives a porous solid with fractal structure. Structural investigations of these colloidal...
Low frequency vibrational modes related to texture in silica aerogels (1990)
Pelous, J., Sauvajol, J.L., Woignier, T., Vacher, R.
Low frequency vibrational modes of silica aerogels have been investigated by Raman spectrometry. The position and lineshape of the peaks observed in the range from 5 to 30 cm-1 appear correlated to...
Low frequency vibrational modes related to texture in silica aerogels (1990)
Pelous, J., Sauvajol, J.L., Woignier, T., Vacher, R.
Low frequency vibrational modes of silica aerogels have been investigated by Raman spectrometry. The position and lineshape of the peaks observed in the range from 5 to 30 cm-1 appear correlated to...
Low frequency vibrational modes related to texture in silica aerogels (1990)
Pelous, J., Sauvajol, J.L., Woignier, T., Vacher, R.
Low frequency vibrational modes of silica aerogels have been investigated by Raman spectrometry. The position and lineshape of the peaks observed in the range from 5 to 30 cm-1 appear correlated to...
A NEUTRON SCATTERING STUDY OF THE DENSITY OF VIBRATIONAL STATES OF FRACTAL SILICA AEROGELS (1989)
Coddens, G., Vacher, R., Woignier, T., Pelous, J., Courtens, E.
The various methods to measure the density of states by neutron inelastic scattering are discussed. Purely incoherent scattering data on silica aerogels have been obtained by taking the difference...
LOW FREQUENCY RAMAN STUDY OF THE HARMONIC VIBRATIONAL MODES IN SILICA AEROGELS (1989)
Sauvajol, J., Pelous, J., Woignier, T., Vacher, R.
The vibrational properties of silica aerogels are investigated by low frequency Raman spectrometry. The mean feature of the spectra is a characteristic peak related to the vibrational mode of the...
ON THE FRACTAL STRUCTURE OF SILICA AEROGELS (1989)
Vacher, R., Woignier, T., Phalippou, J., Pelous, J., Courtens, E.
Both neutrally reacted and base catalyzed silica aerogels can be prepared which are fractals over several orders of magnitude in length. The concept of mutual self-similarity is explained in some...
STRUCTURAL EFFECTS ON BRILLOUIN SCATTERING FROM SILICA AEROGELS (1989)
Pelous, J., Courtens, E., Vacher, R., Woignier, T.
Brillouin scattering spectroscopy on silica aerogels is described. Our previous results on neutrally reacted materials are compared to new data on base catalyzed ones. The same crossover expression...
A NEUTRON SCATTERING STUDY OF THE DENSITY OF VIBRATIONAL STATES OF FRACTAL SILICA AEROGELS (1989)
Coddens, G., Vacher, R., Woignier, T., Pelous, J., Courtens, E.
The various methods to measure the density of states by neutron inelastic scattering are discussed. Purely incoherent scattering data on silica aerogels have been obtained by taking the difference...
LOW FREQUENCY RAMAN STUDY OF THE HARMONIC VIBRATIONAL MODES IN SILICA AEROGELS (1989)
Sauvajol, J., Pelous, J., Woignier, T., Vacher, R.
The vibrational properties of silica aerogels are investigated by low frequency Raman spectrometry. The mean feature of the spectra is a characteristic peak related to the vibrational mode of the...
ON THE FRACTAL STRUCTURE OF SILICA AEROGELS (1989)
Vacher, R., Woignier, T., Phalippou, J., Pelous, J., Courtens, E.
Both neutrally reacted and base catalyzed silica aerogels can be prepared which are fractals over several orders of magnitude in length. The concept of mutual self-similarity is explained in some...
STRUCTURAL EFFECTS ON BRILLOUIN SCATTERING FROM SILICA AEROGELS (1989)
Pelous, J., Courtens, E., Vacher, R., Woignier, T.
Brillouin scattering spectroscopy on silica aerogels is described. Our previous results on neutrally reacted materials are compared to new data on base catalyzed ones. The same crossover expression...
A NEUTRON SCATTERING STUDY OF THE DENSITY OF VIBRATIONAL STATES OF FRACTAL SILICA AEROGELS (1989)
Coddens, G., Vacher, R., Woignier, T., Pelous, J., Courtens, E.
The various methods to measure the density of states by neutron inelastic scattering are discussed. Purely incoherent scattering data on silica aerogels have been obtained by taking the difference...
LOW FREQUENCY RAMAN STUDY OF THE HARMONIC VIBRATIONAL MODES IN SILICA AEROGELS (1989)
Sauvajol, J., Pelous, J., Woignier, T., Vacher, R.
The vibrational properties of silica aerogels are investigated by low frequency Raman spectrometry. The mean feature of the spectra is a characteristic peak related to the vibrational mode of the...
ON THE FRACTAL STRUCTURE OF SILICA AEROGELS (1989)
Vacher, R., Woignier, T., Phalippou, J., Pelous, J., Courtens, E.
Both neutrally reacted and base catalyzed silica aerogels can be prepared which are fractals over several orders of magnitude in length. The concept of mutual self-similarity is explained in some...
STRUCTURAL EFFECTS ON BRILLOUIN SCATTERING FROM SILICA AEROGELS (1989)
Pelous, J., Courtens, E., Vacher, R., Woignier, T.
Brillouin scattering spectroscopy on silica aerogels is described. Our previous results on neutrally reacted materials are compared to new data on base catalyzed ones. The same crossover expression...
He, J., Sapriel, J., Chavignon, J., Azoulay, R., Dugrand, L., Mollot, F., ...
Direct acoustic modes (Brillouin lines) as well as folded acoustic modes at frequencies higher and lower than the Brillouin lines are simultaneously observed. Both LA and TA polarizations are...
He, J., Sapriel, J., Chavignon, J., Azoulay, R., Dugrand, L., Mollot, F., ...
Direct acoustic modes (Brillouin lines) as well as folded acoustic modes at frequencies higher and lower than the Brillouin lines are simultaneously observed. Both LA and TA polarizations are...
He, J., Sapriel, J., Chavignon, J., Azoulay, R., Dugrand, L., Mollot, F., ...
Direct acoustic modes (Brillouin lines) as well as folded acoustic modes at frequencies higher and lower than the Brillouin lines are simultaneously observed. Both LA and TA polarizations are...
Pelous, J., Essabouri, A., Vacher, R.
Rayleigh-Brillouin scattering measurements have been performed in (LiCl)x(H2O)1-x. The first stage of crystallization, during heat treatment near Tg, investigated by intensity measurements vs time...
« Glassy » and plastic crystals of cyanoadamantane : a Brillouin scattering investigation (1985)
Bonnet, J.P., Boissier, M., Pelous, J., Vacher, R., Descamps, M., Sauvajol, J.L.
The elastic constants of cyanoadamantane have been measured in the plastic and « glassy » crystal phases. A special attention has been given to the temperature evolution of C11 as well as to the...
Pelous, J., Essabouri, A., Vacher, R.
Rayleigh-Brillouin scattering measurements have been performed in (LiCl)x(H2O)1-x. The first stage of crystallization, during heat treatment near Tg, investigated by intensity measurements vs time...
« Glassy » and plastic crystals of cyanoadamantane : a Brillouin scattering investigation (1985)
Bonnet, J.P., Boissier, M., Pelous, J., Vacher, R., Descamps, M., Sauvajol, J.L.
The elastic constants of cyanoadamantane have been measured in the plastic and « glassy » crystal phases. A special attention has been given to the temperature evolution of C11 as well as to the...
Pelous, J., Essabouri, A., Vacher, R.
Rayleigh-Brillouin scattering measurements have been performed in (LiCl)x(H2O)1-x. The first stage of crystallization, during heat treatment near Tg, investigated by intensity measurements vs time...
« Glassy » and plastic crystals of cyanoadamantane : a Brillouin scattering investigation (1985)
Bonnet, J.P., Boissier, M., Pelous, J., Vacher, R., Descamps, M., Sauvajol, J.L.
The elastic constants of cyanoadamantane have been measured in the plastic and « glassy » crystal phases. A special attention has been given to the temperature evolution of C11 as well as to the...
ACOUSTIC MODES IN Ga1-xAlxAs CRYSTALS AND RELATED SUPERLATTICES (1984)
Sapriel, J., Michel, J., Toledano, J., Vacher, R.
This is a parallel study of Brillouin and Raman scattering. The additional Raman modes in the superlattices can be interpreted as due to an acousto-optical interaction with phonons of different...
Incommensurate phase of quartz. - II : Brillouin scattering studies (1984)
Berge, B., Dolino, G., Vallade, M., Boissier, M., Vacher, R.
The recently discovered incommensurate phase of quartz close to the α-β transition has been investigated using Brillouin scattering. The frequency and the damping of the longitudinal (LA)...
ACOUSTIC MODES IN Ga1-xAlxAs CRYSTALS AND RELATED SUPERLATTICES (1984)
Sapriel, J., Michel, J., Toledano, J., Vacher, R.
This is a parallel study of Brillouin and Raman scattering. The additional Raman modes in the superlattices can be interpreted as due to an acousto-optical interaction with phonons of different...
Incommensurate phase of quartz. - II : Brillouin scattering studies (1984)
Berge, B., Dolino, G., Vallade, M., Boissier, M., Vacher, R.
The recently discovered incommensurate phase of quartz close to the α-β transition has been investigated using Brillouin scattering. The frequency and the damping of the longitudinal (LA)...
ACOUSTIC MODES IN Ga1-xAlxAs CRYSTALS AND RELATED SUPERLATTICES (1984)
Sapriel, J., Michel, J., Toledano, J., Vacher, R.
This is a parallel study of Brillouin and Raman scattering. The additional Raman modes in the superlattices can be interpreted as due to an acousto-optical interaction with phonons of different...
Incommensurate phase of quartz. - II : Brillouin scattering studies (1984)
Berge, B., Dolino, G., Vallade, M., Boissier, M., Vacher, R.
The recently discovered incommensurate phase of quartz close to the α-β transition has been investigated using Brillouin scattering. The frequency and the damping of the longitudinal (LA)...
Acoustic phonon absorption and dispersion in hydroxyl-doped KCl crystals at low temperatures (1983)
Berret, J.F., Pelous, J., Vacher, R.
The acoustic properties of hydroxyl-doped KCl crystals have been measured by Brillouin scattering in the temperature range 1 to 50 K. For samples with OH- content higher than 200 ppm, two features...
Acoustic phonon absorption and dispersion in hydroxyl-doped KCl crystals at low temperatures (1983)
Berret, J.F., Pelous, J., Vacher, R.
The acoustic properties of hydroxyl-doped KCl crystals have been measured by Brillouin scattering in the temperature range 1 to 50 K. For samples with OH- content higher than 200 ppm, two features...
Acoustic phonon absorption and dispersion in hydroxyl-doped KCl crystals at low temperatures (1983)
Berret, J.F., Pelous, J., Vacher, R.
The acoustic properties of hydroxyl-doped KCl crystals have been measured by Brillouin scattering in the temperature range 1 to 50 K. For samples with OH- content higher than 200 ppm, two features...
BRILLOUIN SCATTERING FROM AMORPHOUS POLYMERS AT LOW TEMPERATURES (1982)
Schmidt, M., Vacher, R., Pelous, J., Hunklinger, S.
For three different polymers (polymethylmethacrylate (PMMA), polystyrene (PS), and polycarbonate (PC) ) sound velocity and attenuation of 18 GHz longitudinal phonons were measured in the temperature...
Pelous, J., Essabouri, A., Vacher, R.
We have studied by Brillouin scattering the attenuation and velocity of hypersonic waves in a glass formed by quenching an aqueous solution of LiCl (molar electrolyte content : 10 %). This material...
Singh, G., Vacher, R., Calemczuk, R.
Cyclohexanol exhibits a "glassy" crystal phase at low temperatures. In this phase the mass centers of the molecules form a crystalline lattice, but the orientations of the molecules are disordered....
GLASS-LIKE ANOMALIES IN THE HYPERSONIC PROPERTIES OF OH- DOPED KCl CRYSTALS (1982)
Vacher, R., Pelous, J., Berret, J., Schmidt, M.
Using the Brillouin scattering technique, we have measured the velocity and attenuation of 30 GHz longitudinal hypersonic waves down to 1 K for OH- doped KCl crystals : we present here the results...
LIGHT SCATTERING FROM ACOUSTIC AND LOW-FREQUENCY VIBRATIONAL MODES IN BORATE GLASSES (1982)
Lorösch, J., Couzi, M., Pelous, J., Vacher, R., Levasseur, A.
Brillouin and low frequency Raman scattering experiments have been performed on series of B2O3 - x M2O glasses where M = Li, Na, K, Rb, Cs, Tl. The concentration and composition dependences of the...
BRILLOUIN SCATTERING FROM AMORPHOUS POLYMERS AT LOW TEMPERATURES (1982)
Schmidt, M., Vacher, R., Pelous, J., Hunklinger, S.
For three different polymers (polymethylmethacrylate (PMMA), polystyrene (PS), and polycarbonate (PC) ) sound velocity and attenuation of 18 GHz longitudinal phonons were measured in the temperature...
Pelous, J., Essabouri, A., Vacher, R.
We have studied by Brillouin scattering the attenuation and velocity of hypersonic waves in a glass formed by quenching an aqueous solution of LiCl (molar electrolyte content : 10 %). This material...
Singh, G., Vacher, R., Calemczuk, R.
Cyclohexanol exhibits a "glassy" crystal phase at low temperatures. In this phase the mass centers of the molecules form a crystalline lattice, but the orientations of the molecules are disordered....
GLASS-LIKE ANOMALIES IN THE HYPERSONIC PROPERTIES OF OH- DOPED KCl CRYSTALS (1982)
Vacher, R., Pelous, J., Berret, J., Schmidt, M.
Using the Brillouin scattering technique, we have measured the velocity and attenuation of 30 GHz longitudinal hypersonic waves down to 1 K for OH- doped KCl crystals : we present here the results...
LIGHT SCATTERING FROM ACOUSTIC AND LOW-FREQUENCY VIBRATIONAL MODES IN BORATE GLASSES (1982)
Lorösch, J., Couzi, Michel, Pelous, J., Vacher, R., Levasseur, Alain
Brillouin and low frequency Raman scattering experiments have been performed on series of B2O3 - x M2O glasses where M = Li, Na, K, Rb, Cs, Tl. The concentration and composition dependences of the...
BRILLOUIN SCATTERING FROM AMORPHOUS POLYMERS AT LOW TEMPERATURES (1982)
Schmidt, M., Vacher, R., Pelous, J., Hunklinger, S.
For three different polymers (polymethylmethacrylate (PMMA), polystyrene (PS), and polycarbonate (PC) ) sound velocity and attenuation of 18 GHz longitudinal phonons were measured in the temperature...
Pelous, J., Essabouri, A., Vacher, R.
We have studied by Brillouin scattering the attenuation and velocity of hypersonic waves in a glass formed by quenching an aqueous solution of LiCl (molar electrolyte content : 10 %). This material...
Singh, G., Vacher, R., Calemczuk, R.
Cyclohexanol exhibits a "glassy" crystal phase at low temperatures. In this phase the mass centers of the molecules form a crystalline lattice, but the orientations of the molecules are disordered....
GLASS-LIKE ANOMALIES IN THE HYPERSONIC PROPERTIES OF OH- DOPED KCl CRYSTALS (1982)
Vacher, R., Pelous, J., Berret, J., Schmidt, M.
Using the Brillouin scattering technique, we have measured the velocity and attenuation of 30 GHz longitudinal hypersonic waves down to 1 K for OH- doped KCl crystals : we present here the results...
LIGHT SCATTERING FROM ACOUSTIC AND LOW-FREQUENCY VIBRATIONAL MODES IN BORATE GLASSES (1982)
Lorösch, J., Couzi, Michel, Pelous, J., Vacher, R., Levasseur, Alain
Brillouin and low frequency Raman scattering experiments have been performed on series of B2O3 - x M2O glasses where M = Li, Na, K, Rb, Cs, Tl. The concentration and composition dependences of the...
FREQUENCY DEPENDENCE OF SOUND ABSORPTION OF VITREOUS SILICA BETWEEN 10 MHz AND 35 GHz (1981)
Vacher, R., Pelous, J., Plicque, F., Zarembowitch, A.
We present new measurements of the attenuation of ultranonic and hypersonic waves for temperatures ranging from 10 to 300 K in silica glass. The results show that the relaxation process which is...
PHONON DAMPING IN CRYSTALLINE AND AMORPHOUS SOLIDS AT HYPERSONIC FREQUENCIES (1981)
We present new Brillouin scattering measurements, for temperature ranging from 1 K to room temperature in a broad range of insulating solids (crystalline and amorphous solids). We analyse the...
ULTRASONIC RELAXATION IN α-SULFUR (1981)
Boissier, M., Vacher, R., Perrin, B.
We present new measurements of the temperature dependence ofacoustic damping in α-sulfur. The anomalous elastic properties observedin this crystal are described in terms of a "molecular...
FREQUENCY DEPENDENCE OF SOUND ABSORPTION OF VITREOUS SILICA BETWEEN 10 MHz AND 35 GHz (1981)
Vacher, R., Pelous, J., Plicque, F., Zarembowitch, A.
We present new measurements of the attenuation of ultranonic and hypersonic waves for temperatures ranging from 10 to 300 K in silica glass. The results show that the relaxation process which is...
PHONON DAMPING IN CRYSTALLINE AND AMORPHOUS SOLIDS AT HYPERSONIC FREQUENCIES (1981)
We present new Brillouin scattering measurements, for temperature ranging from 1 K to room temperature in a broad range of insulating solids (crystalline and amorphous solids). We analyse the...
ULTRASONIC RELAXATION IN α-SULFUR (1981)
Boissier, M., Vacher, R., Perrin, B.
We present new measurements of the temperature dependence ofacoustic damping in α-sulfur. The anomalous elastic properties observedin this crystal are described in terms of a "molecular...
FREQUENCY DEPENDENCE OF SOUND ABSORPTION OF VITREOUS SILICA BETWEEN 10 MHz AND 35 GHz (1981)
Vacher, R., Pelous, J., Plicque, F., Zarembowitch, A.
We present new measurements of the attenuation of ultranonic and hypersonic waves for temperatures ranging from 10 to 300 K in silica glass. The results show that the relaxation process which is...
PHONON DAMPING IN CRYSTALLINE AND AMORPHOUS SOLIDS AT HYPERSONIC FREQUENCIES (1981)
We present new Brillouin scattering measurements, for temperature ranging from 1 K to room temperature in a broad range of insulating solids (crystalline and amorphous solids). We analyse the...
ULTRASONIC RELAXATION IN α-SULFUR (1981)
Boissier, M., Vacher, R., Perrin, B.
We present new measurements of the temperature dependence ofacoustic damping in α-sulfur. The anomalous elastic properties observedin this crystal are described in terms of a "molecular...
The elastic anomaly of NaCN at 284 K (1980)
Boissier, M., Vacher, R., Fontaine, D., Pick, R.M.
The Brillouin frequency and linewidth of longitudinal phonons (q // e // (1, 0, 0)) and soft transverse phonons (q // (1, 1, 0) ; e // (0, 0,1)) have been measured in NaCN in its cubic phase above...
The elastic anomaly of NaCN at 284 K (1980)
Boissier, M., Vacher, R., Fontaine, D., Pick, R.M.
The Brillouin frequency and linewidth of longitudinal phonons (q // e // (1, 0, 0)) and soft transverse phonons (q // (1, 1, 0) ; e // (0, 0,1)) have been measured in NaCN in its cubic phase above...
The elastic anomaly of NaCN at 284 K (1980)
Boissier, M., Vacher, R., Fontaine, D., Pick, R.M.
The Brillouin frequency and linewidth of longitudinal phonons (q // e // (1, 0, 0)) and soft transverse phonons (q // (1, 1, 0) ; e // (0, 0,1)) have been measured in NaCN in its cubic phase above...
The elastic anomaly of KCN at 168 K (1978)
Boissier, M., Vacher, R., Fontaine, D., Pick, R.M.
The Brillouin linewidths of longitudinal phonons (qllell[1, 0, 0]) and soft transverse phonons (q//[1, 1, 0] ; e//[0, 0, 1]) have been measured for the first time in KCN in its cubic phase above the...
The elastic anomaly of KCN at 168 K (1978)
Boissier, M., Vacher, R., Fontaine, D., Pick, R.M.
The Brillouin linewidths of longitudinal phonons (qllell[1, 0, 0]) and soft transverse phonons (q//[1, 1, 0] ; e//[0, 0, 1]) have been measured for the first time in KCN in its cubic phase above the...
The elastic anomaly of KCN at 168 K (1978)
Boissier, M., Vacher, R., Fontaine, D., Pick, R.M.
The Brillouin linewidths of longitudinal phonons (qllell[1, 0, 0]) and soft transverse phonons (q//[1, 1, 0] ; e//[0, 0, 1]) have been measured for the first time in KCN in its cubic phase above the...
Low-energy excitations and hypersonic properties at low temperatures in amorphous media (1977)
Brillouin scattering measurements of velocity and inverse mean free path of phonons are presented for three silicate glasses and two samples of PMMA, in the temperature range from 1.7 to 15 K. The...
Low-energy excitations and hypersonic properties at low temperatures in amorphous media (1977)
Brillouin scattering measurements of velocity and inverse mean free path of phonons are presented for three silicate glasses and two samples of PMMA, in the temperature range from 1.7 to 15 K. The...
Low-energy excitations and hypersonic properties at low temperatures in amorphous media (1977)
Brillouin scattering measurements of velocity and inverse mean free path of phonons are presented for three silicate glasses and two samples of PMMA, in the temperature range from 1.7 to 15 K. The...
Interferential spectrometry in brillouin scattering (1976)
The influence ofinhomogeneity and of anisotropy of the flux scattered in the aperture of the spectrometer on the position and the lineshape of the recorded Brillouin spectrum is analysed for the...
Interferential spectrometry in brillouin scattering (1976)
The influence ofinhomogeneity and of anisotropy of the flux scattered in the aperture of the spectrometer on the position and the lineshape of the recorded Brillouin spectrum is analysed for the...
Interferential spectrometry in brillouin scattering (1976)
The influence ofinhomogeneity and of anisotropy of the flux scattered in the aperture of the spectrometer on the position and the lineshape of the recorded Brillouin spectrum is analysed for the...
Anisotropie de la diffusion Rayleigh dans un cristal plastique : le succinonitrile (1975)
Boyer, L., Vacher, R., Cecchi, L.
L'étude expérimentale de la raie Rayleigh dépolarisée révèle une forte anisotropie de l'intensité diffusée. L'effet, attribué à l'existence d'orientations privilégiées des molécules dans...
Anisotropie de la diffusion Rayleigh dans un cristal plastique : le succinonitrile (1975)
Boyer, L., Vacher, R., Cecchi, L.
L'étude expérimentale de la raie Rayleigh dépolarisée révèle une forte anisotropie de l'intensité diffusée. L'effet, attribué à l'existence d'orientations privilégiées des molécules dans...
Anisotropie de la diffusion Rayleigh dans un cristal plastique : le succinonitrile (1975)
Boyer, L., Vacher, R., Cecchi, L.
L'étude expérimentale de la raie Rayleigh dépolarisée révèle une forte anisotropie de l'intensité diffusée. L'effet, attribué à l'existence d'orientations privilégiées des molécules dans...
Rayleigh scattering from pivalic acid (1974)
Beysens, D., Vacher, R., Searby, G.M., Boyer, L., Adam, M.
Both the polarized and depolarized spectra of Rayleigh scattering from pivalic acid have been measured with high precision. The relaxation time for molecular reorientation and the energy of...
Rayleigh scattering from pivalic acid (1974)
Beysens, D., Vacher, R., Searby, G.M., Boyer, L., Adam, M.
Both the polarized and depolarized spectra of Rayleigh scattering from pivalic acid have been measured with high precision. The relaxation time for molecular reorientation and the energy of...
Rayleigh scattering from pivalic acid (1974)
Beysens, D., Vacher, R., Searby, G.M., Boyer, L., Adam, M.
Both the polarized and depolarized spectra of Rayleigh scattering from pivalic acid have been measured with high precision. The relaxation time for molecular reorientation and the energy of...
Dispersion des ondes acoustiques dans le succinonitrile en phase plastique (1972)
Fontaine, H., Fouret, R., Boyer, L., Vacher, R.
On montre que la dispersion des vitesses observée dans un cristal plastique peut s'interpréter en admettant l'existence d'un mécanisme de réaction. A partir des équations de la thermodynamique...
Dispersion des ondes acoustiques dans le succinonitrile en phase plastique (1972)
Fontaine, H., Fouret, R., Boyer, L., Vacher, R.
On montre que la dispersion des vitesses observée dans un cristal plastique peut s'interpréter en admettant l'existence d'un mécanisme de réaction. A partir des équations de la thermodynamique...
Dispersion des ondes acoustiques dans le succinonitrile en phase plastique (1972)
Fontaine, H., Fouret, R., Boyer, L., Vacher, R.
On montre que la dispersion des vitesses observée dans un cristal plastique peut s'interpréter en admettant l'existence d'un mécanisme de réaction. A partir des équations de la thermodynamique...
Adam, M., Boyer, L., Vacher, R., Berge, P., Cecchi, L.
Le spectre de diffusion du succinonitrile dans la phase plastique présente une composante centrée sur la fréquence excitatrice, intense, large et fortement dépolarisée. Une étude expérimentale...
Adam, M., Boyer, L., Vacher, R., Berge, P., Cecchi, L.
Le spectre de diffusion du succinonitrile dans la phase plastique présente une composante centrée sur la fréquence excitatrice, intense, large et fortement dépolarisée. Une étude expérimentale...
Adam, M., Boyer, L., Vacher, R., Berge, P., Cecchi, L.
Le spectre de diffusion du succinonitrile dans la phase plastique présente une composante centrée sur la fréquence excitatrice, intense, large et fortement dépolarisée. Une étude expérimentale...
Vacher, R., Boyer, L., Cecchi, L.
Une analyse des différents procédés de filtrage de la raie Rayleigh met en évidence plusieurs avantages de l'interféromètre de Fabry-Pérot utilisé en réflexion. L'étude théorique du...
Mesure des constantes élastiques du quartz par diffusion Brillouin (1970)
Cecchi, L., Vacher, R., Danyach, L.
Après avoir rappelé le principe de la méthode de mesure des constantes élastiques par diffusion Brillouin, les auteurs décrivent son application au cas du quartz et donnent les valeurs...
Vacher, R., Boyer, L., Cecchi, L.
Une analyse des différents procédés de filtrage de la raie Rayleigh met en évidence plusieurs avantages de l'interféromètre de Fabry-Pérot utilisé en réflexion. L'étude théorique du...
Mesure des constantes élastiques du quartz par diffusion Brillouin (1970)
Cecchi, L., Vacher, R., Danyach, L.
Après avoir rappelé le principe de la méthode de mesure des constantes élastiques par diffusion Brillouin, les auteurs décrivent son application au cas du quartz et donnent les valeurs...
Vacher, R., Boyer, L., Cecchi, L.
Une analyse des différents procédés de filtrage de la raie Rayleigh met en évidence plusieurs avantages de l'interféromètre de Fabry-Pérot utilisé en réflexion. L'étude théorique du...
Mesure des constantes élastiques du quartz par diffusion Brillouin (1970)
Cecchi, L., Vacher, R., Danyach, L.
Après avoir rappelé le principe de la méthode de mesure des constantes élastiques par diffusion Brillouin, les auteurs décrivent son application au cas du quartz et donnent les valeurs...