Fragility and elasticity - a new perspective (2009)
The fragility (the abnormally strong temperature dependence of the viscosity) of highly viscous liquids is shown to have two sources. The first is the temperature dependence of the barriers between...
An asymmetry model for the highly viscous flow (2008)
The shear flow is modeled in terms of local structural rearrangements. Most of these rearrangements are strongly asymmetric, because the embedding matrix tends to be elastically adapted to the...
An atomic mechanism for the boson peak in metallic glasses (2008)
The boson peak in metallic glasses is modeled in terms of local structural shear rearrangements. Using Eshelby's solution of the corresponding elasticity theory problem (J. D. Eshelby, Proc. Roy....
An Eshelby model for the highly viscous flow (2007)
The shear flow and the dielectric alpha-process in molecular glass formers is modeled in terms of local structural rearrangements which reverse a strong local shear. Using Eshelby's solution of the...
Mechanical and dielectric relaxation spectra in seven highly viscous glass formers (2007)
Published dielectric and shear data of six molecular glass formers and one polymer are evaluated in terms of a spectrum of thermally activated processes, with the same barrier density for the...
Dielectric and thermal relaxation in the energy landscape (2006)
Buchenau, U., Zorn, R., Ohl, M., Wischnewski, A.
We derive an energy landscape interpretation of dielectric relaxation times in undercooled liquids, comparing it to the traditional Debye and Gemant-DiMarzio-Bishop pictures. The interaction between...
A new interpretation of dielectric data in molecular glass formers (2006)
Buchenau, U., Ohl, M., Wischnewski, A.
This version is available at the following Publisher URL: http://jcp.aip.org
A new interpretation of dielectric data in molecular glass formers (2005)
Buchenau, U., Ohl, M., Wischnewski, A.
Literature dielectric data of glycerol, propylene carbonate and ortho-terphenyl (OTP) show that the measured dielectric relaxation is a decade faster than the Debye expectation, but still a decade...
Neutron scattering study of the vibrations in vitreous silica and germania (2005)
Fabiani, E., Fontana, A., Buchenau, U.
The incoherent approximation for the determination of the vibrational density of states of glasses from inelastic neutron or x-ray scattering data is extended to treat the coherent scattering. The...
On the energy landscape at the glass transition (2004)
A recent hypothesis claims that the glass transition itself, though it is a very pronounced relaxation peak, is no separate relaxation process at all, but is just the breakdown of the shear modulus...
Neutron scattering evidence on the nature of the boson peak (2004)
Buchenau, U., Wischnewski, A., Ohl, M., Fabiani, E.
A close inspection of neutron spectra of glass formers in the frequency region above the boson peak does not show the constant eigenvalue density expected for a random dynamical matrix, but a slow...
Fragility and compressibility at the glass transition (2004)
Isothermal compressibilities and Brillouin sound velocities from the literature allow to separate the compressibility at the glass transition into a high-frequency vibrational and a low-frequency...
Fragility and compressibility at the glass transition (2004)
This version is available at the following Publisher URL: http://prb.aps.org
This is a comment on the beautiful results of Jeppe Dyre and Niels Boie Olsen, published as a recent Physical Review Letter.
Instrumental setup for polarized neutron scattering experiments (2003)
Schmidt, W., Ohl, M., Ruppert, H., Buchenau, U.
This version is available at the following Publisher URL: http://jap.aip.org
Energy landscape - a key concept for the dynamics of glasses and liquids (2002)
There is a growing belief that the mode coupling theory is the proper microscopic theory for the dynamics of the undercooled liquid above a critical temperature T_c. In addition, there is some...
The breakdown of the shear modulus at the glass transition (2002)
The glass transition is described in terms of thermally activated local structural rearrangements, the secondary relaxations of the glass phase. The interaction between these secondary relaxations...
Intermediate length scale dynamics of polyisobutylene (2002)
Farago, B., Arbe, A., Colmenero, J., Faust, R., Buchenau, U., Richter, D.
This version is available at the following Publisher URL: http://pre.aps.org
Intermediate range structure and low energy dynamics of densified vitreous silica. (2001)
Inamura, Y, Arai, M, Nakamura, M, Otomo, T, Kitamura, N, Bennington, S M, ...
Mechanical relaxation in glasses and the glass transition (2001)
This version is available at the following Publisher URL: http://prb.aps.org
Schmidt, W., Ohl, M., Buchenau, U.
This version is available at the following Publisher URL: http://prl.aps.org
Mechanical Relaxation in Glasses and at the Glass Transition (2000)
The Gilroy-Phillips model of relaxational jumps in asymmetric double-well potentials, developed for the Arrhenius-type secondary relaxations of the glass phase, is extended to a formal description of...
Non-Gaussian behavior of crystalline and amorphous phases of polyethylene (2000)
Kanaya, T., Buchenau, U., Koizumi, S., Tsukushi, I., Kaji, K.
This version is available at the URL: http://prb.aps.org/
Fontana, A., Dell'Anna, R., Montagna, M., Rossi, F., Viliani, G., Ruocco, G., ...
New Raman and incoherent neutron scattering data at various temperatures and molecular dynamic simulations in amorphous silica, are compared to obtain the Raman coupling coefficient $C(\omega)$ and,...
Spectrum of Fast Dynamics in Glass Forming Liquids: Does the "Knee" Exist? (1999)
Gapinski, J., Steffen, W., Patkowski, A., Sokolov, A. P., Kisliuk, A., Buchenau, U., ...
Spatial correlations in polycarbonates: Neutron scattering and simulation (1999)
Eilhard, J., Zirkel, A., Tschop, W., Hahn, O., Kremer, Kurt, Schärpf, O., ...
Sound waves and other modes in the strong glass former B2O3 (1998)
Engberg, D, Wischnewski, A, Buchenau, U, Borjesson, L, Dianoux, A J, Sokolov, A P, ...
Sound waves and other modes in the strong glassformer B2O3 (1997)
Börjesson, L., Buchenau, U., Dianoux, A. J., Engberg, D., Sokolov, A. P., Wischnewski, A.
Fast relaxations in a silicate glass. (1993)
Buchenau, U., Nuecker, N., Dianoux, A.J., Krause, D.
Disordered Materials II, Grenoble, F, March 22-24, 1993
VIBRATIONAL DENSITY OF STATES FOR LOW-DENSITY SILICA AEROGELS (1989)
Reichenauer, G., Buchenau, U., Fricke, J.
The vibrational density of states for highly porous silica aerogels (ρ = 120 kg/m3 and 250 kg/m3) were studied with inelastic neutron scattering in the frequency range from 0.02 THz to 2 THz....
VIBRATIONAL DENSITY OF STATES FOR LOW-DENSITY SILICA AEROGELS (1989)
Reichenauer, G., Buchenau, U., Fricke, J.
The vibrational density of states for highly porous silica aerogels (ρ = 120 kg/m3 and 250 kg/m3) were studied with inelastic neutron scattering in the frequency range from 0.02 THz to 2 THz....
VIBRATIONAL DENSITY OF STATES FOR LOW-DENSITY SILICA AEROGELS (1989)
Reichenauer, G., Buchenau, U., Fricke, J.
The vibrational density of states for highly porous silica aerogels (ρ = 120 kg/m3 and 250 kg/m3) were studied with inelastic neutron scattering in the frequency range from 0.02 THz to 2 THz....
Dynamics of glassy and liquid selenium. (1989)
Phillips, W.A., Buchenau, U., Nuecker, N., Dianoux, A., Petry, W.
Physical Review Letters, 63(1989) S.2381-84
Neutron scattering from low-frequency excitations in amorphous germanium. (1988)
Buchenau, U., Prager, M., Kamitakahara, W.A., Shanks, H.R., Nuecker, N.
Europhysics Letters, 6(1988) S.695-700
Structural relaxation in vitreous silica. (1988)
Buchenau, U., Zhou, H.M., Nuecker, N., Gilroy, K.S., Philips, W.A.
Physical Review Letters, 60(1988) S.1318-21
Neutronenstreuung an niederfrequenten Anregungen im amorphen Germanium. (1987)
Kamitakahara, W.A., Nuecker, N., Prager, M., Buchenau, U.
Fruehjahrstagung DPG, Duenne Schichten, Dynamik und Statistische Physik, Halbleiterphysik, Magnetismus, Metallphysik, Tiefe Temperaturen, Muenster, 9.-13.Maerz 1987
Low frequency excitations in vitreous silica. (1986)
Dianoux, A.J., Buchenau, U., Prager, M., Nuecker, N.
Physica B, 138(1986) S.264-68
Measurement of phonon densities of states for pure and hydrogenated amorphous silicon. (1984)
Kamitakahara, W.A., Shanks, H.R., Mc Clelland, J.F., Buchenau, U., Gompf, F., Pintschovius, L.
Physical Review Letters, 52(1984) S.644-47
Elastische Konstanten von A15-Nb§3Ge. (1984)
Mueller, P., Buchenau, U., Nuecker, N., Renker, B., Mueller, A.
48.Physikertagung gemeinsam mit der Fruehjahrstagung DPG, Festkoerperphysik, Muenster, 12.-17.Maerz 1984.
Elastic constants of A15-Nb§3Ge. (1984)
Mueller, U., Buchenau, U., Nuecker, N., Renker, B., Mueller, A.
Eckern, U.; Schmid, A.; Weber, W.; Wuehl, H. [Hrsg.]
Neutron scattering study of the low-frequency vibrations in vitreous silica. (1984)
Buchenau, U., Nuecker, N., Dianoux, A.J.
Physical Review Letters, 53(1984) S.2316
Gitterdynamik von kubischem Lanthan bei Raumtemperatur. (1983)
Nuecker, N., Buchenau, U., Schober, H.R.
Fruehjahrstagung des Arbeitskreises Festkoerperphysik bei der Deutschen Physikalischen Gesellschaft, Freudenstadt, 21.-25.Maerz 1983
COHERENT NEUTRON SCATTERING FROM POLYCRYSTALS (1981)
Buchenau, U., Schober, H., Wagner, R.
Phonon dispersion curves are mostly determined by coherent neutron scattering from single crystals. For a number of materials, however, large enough single crystals are not obtainable. We used the...
COHERENT NEUTRON SCATTERING FROM POLYCRYSTALS (1981)
Buchenau, U., Schober, H., Wagner, R.
Phonon dispersion curves are mostly determined by coherent neutron scattering from single crystals. For a number of materials, however, large enough single crystals are not obtainable. We used the...
COHERENT NEUTRON SCATTERING FROM POLYCRYSTALS (1981)
Buchenau, U., Schober, H., Wagner, R.
Phonon dispersion curves are mostly determined by coherent neutron scattering from single crystals. For a number of materials, however, large enough single crystals are not obtainable. We used the...