Sun, 27 Jul 2008 06:08:33 BST CiteULike: Tag glass http://www.citeulike.org/tag/glass CiteULike.org en-gb Copyright © 2004-2008 citeulike.org http://www.citeulike.org/user/weeks/article/1304927 <i>Physical Review E, Vol. 58, No. 5. (November 1998), 6073.</i><br /><br />Dynamic light-scattering measurements are reported for suspensions at concentrations in the vicinity of the glass transition. In a mixture of identically sized but optically different particles having hard-sphere-like interactions; we project out the incoherent (or self-) intermediate scattering functions by adjusting the refractive index of the suspending liquid until scattering from the structure is suppressed. Due to polydispersity; crystallization is sufficiently slow so that good estimates of ensemble-averaged quantities can be measured for the metastable fluid states. Crystallization of the suspensions is still exploited; however; to set the volume fraction scale in terms of effective hard spheres and to eliminate (coherent) scattering from the structure. The glass-transition volume fraction is identified by the value where large-scale particle motion ceases. The nonequilibrium nature of the glass state is evidenced by the dependence on the waiting time of the long time decay of the relaxation functions. The self-intermediate scattering functions show negligible deviation from Gaussian behavior up to the onset of large-scale diffusion in the fluid or the onset of waiting time effects in the glass. Measurement of the self-intermediate scattering function of suspensions of hard spherical particles near the glass transition W van Megen TC Mortensen SR Williams J Müller doi:10.1103/PhysRevE.58.6073 Physical Review E, Vol. 58, No. 5. (November 1998), 6073. 2007-05-18T07:35:41-00:00 1998 Physical Review E 58 5 6073 American Physical Society aging colloids dls glass hard-sphere http://www.citeulike.org/user/weeks/article/1706975 <i>Physical Review E, Vol. 59, No. 1. (January 1999), 715.</i><br /><br />A liquid-glass transition was observed experimentally in a new system; an oil-in-water emulsion. Dynamic light scattering was employed to obtain the intermediate scattering function f(q;t) for a range of volume fractions φ and scattering vectors q . The results are compared with predictions of the mode coupling theory. While the usual idealized version of the theory provides accurate fits to the data on the liquid side of the transition; fits for volume fractions near the transition and in the glass phase were found to require the extended version; presumably due to an additional decay mechanism related to the deformability of the oil droplets. Emulsion glasses: A dynamic light-scattering study Hu Gang AH Krall HZ Cummins DA Weitz doi:10.1103/PhysRevE.59.715 Physical Review E, Vol. 59, No. 1. (January 1999), 715. 2007-09-29T02:17:32-00:00 1999 Physical Review E 59 1 715 American Physical Society dls emulsion glass mct http://www.citeulike.org/user/weeks/article/1706973 <i>Physical Review E, Vol. 56, No. 3. (1997), 3150.</i><br /><br />We present an experimental study of the frequency ω dependence and volume fraction φ dependence of the complex shear modulus G * (ω;φ) of monodisperse emulsions which have been concentrated by an osmotic pressure Π. At a given φ; the elastic storage modulus G ′ (ω)=Re[ G * (ω)] exhibits a low-frequency plateau G p ′ ; dominating the dissipative loss modulus G ′′ (ω)=Im[ G * (ω)] which exhibits a minimum. Above a critical packing fraction φ c ; we find that both Π(φ) and G p ′ (φ) increase quasilinearly; scaling as (φ-φ c ) μ ; where φ c ≈φ c rcp ; the volume fraction of a random close packing of spheres; and μ is an exponent close to unity. To explain this result; we develop a model of disordered droplets which interact through an effective repulsive anharmonic potential; based on results obtained for a compressed droplet. A simulation based on this model yields a calculated static shear modulus G and osmotic pressure Π that are in excellent agreement with the experimental values of G p ′ and Π. Osmotic pressure and viscoelastic shear moduli of concentrated emulsions TG Mason Martin-D Lacasse Gary Grest Dov Levine J Bibette DA Weitz doi:10.1103/PhysRevE.56.3150 Physical Review E, Vol. 56, No. 3. (1997), 3150. 2007-09-29T02:16:47-00:00 1997 Physical Review E 56 3 3150 American Physical Society emulsion glass rheology http://www.citeulike.org/user/weeks/article/1304894 <i>Physical Review E, Vol. 49, No. 5. (May 1994), pp. 4206-4220.</i><br /><br />Suspensions of identical particles with hard-sphere-like interactions are studied at concentrations for which the equilibrium state is crystalline. Dynamic light scattering measurements on these suspensions; in their metastable amorphous states prior to crystallization; identify the kinetic glass transition (GT) by the arrest of particle concentration fluctuations on the experimental time scale. This kinetic glass transition coincides with a spectacular change in the mechanism of crystallization from the formation of small crystals; which appear homogeneously nucleated throughout the sample at concentrations below the transition; to the growth; above the transition; of larger and highly asymmetric crystals whose shape and orientation depend on the shear history of the suspension. The intermediate scattering functions are measured over a time window spanning up to eight decades and for several wave vectors near the position of the main structure factor peak. From an analysis of the data in terms of the idealized version of mode-coupling theory; we conclude that both α and β processes are necessary to describe the slow structural relaxation in the fluid near the GT. The superposition principle of the α process; for the colloidal fluid; and the factorization property of the β process; for the colloidal fluid and glass; are verified. Glass transition in colloidal hard spheres: Measurement and mode-coupling-theory analysis of the coherent intermediate scattering function W van Megen SM Underwood doi:10.1103/PhysRevE.49.4206 Physical Review E, Vol. 49, No. 5. (May 1994), pp. 4206-4220. 2007-05-18T07:16:01-00:00 1994 Physical Review E 49 5 4206 4220 American Physical Society colloids dls glass mct http://www.citeulike.org/user/weeks/article/1706953 <i>Physical Review A, Vol. 43, No. 10. (15 May 1991), pp. 5442-5448.</i><br /><br />The glass transition studied for suspensions of colloidal particles through dynamical light-scattering experiments is analyzed within the mode-coupling theory for the supercooled liquid dynamics. These suspensions are treated as simple atomic systems with a hard-sphere interaction. The scaling properties predicted by the theory are verified. The shape of the master function for the β-relaxation region agrees well with the experimental data. Beta relaxation at the glass transition of hard-spherical colloids W Götze L Sjögren doi:10.1103/PhysRevA.43.5442 Physical Review A, Vol. 43, No. 10. (15 May 1991), pp. 5442-5448. 2007-09-29T02:07:38-00:00 1991 Physical Review A 43 10 5442 5448 American Physical Society colloids glass mct theory http://www.citeulike.org/user/weeks/article/1706951 <i>Physical Review A, Vol. 43, No. 10. (15 May 1991), pp. 5429-5441.</i><br /><br />This paper describes a light-scattering study of the glass transition in nonaqueous suspensions of sterically stabilized colloidal spheres. The observed phase behavior; fluid; crystal; and glass; is consistent with an essentially hard-sphere interaction between the particles. Metastable fluid states were obtained upon shear melting the crystalline phases by tumbling the samples. Their intermediate scattering functions; measured by dynamic light scattering; showed the emergence of a nondecaying component; implying structural arrest; at essentially the same concentration as that at which homogeneously nucleated crystallization was no longer observed. The overall forms of the intermediate scattering functions are consistent with the predictions of mode-coupling theories for the glass transition. Supplementary studies of the static structure factors indicated only short-ranged spatial order for particle concentrations ranging from the equilibrium fluid through the metastable fluid to the glass. Dynamic light-scattering study of the glass transition in a colloidal suspension W van Megen PN Pusey doi:10.1103/PhysRevA.43.5429 Physical Review A, Vol. 43, No. 10. (15 May 1991), pp. 5429-5441. 2007-09-29T02:06:40-00:00 1991 Physical Review A 43 10 5429 5441 American Physical Society colloids dls glass mct http://www.citeulike.org/user/weeks/article/1309740 <i>Science, Vol. 267, No. 5206. (31 March 1995), pp. 1935-1939.</i><br /><br />Various static and dynamic phenomena displayed by glass-forming liquids, particularly those near the so-called "fragile" limit, emerge as manifestations of the multidimensional complex topography of the collective potential energy function. These include non-Arrhenius viscosity and relaxation times, bifurcation between the [agr]- and [beta]-relaxation processes, and a breakdown of the Stokes-Einstein relation for self-diffusion. This multidimensional viewpoint also produces an extension of the venerable Lindemann melting criterion and provides a critical evaluation of the popular "ideal glass state" concept. 10.1126/science.267.5206.1935 A Topographic View of Supercooled Liquids and Glass Formation Frank Stillinger doi:10.1126/science.267.5206.1935 Science, Vol. 267, No. 5206. (31 March 1995), pp. 1935-1939. 2007-05-19T22:04:07-00:00 1995 Science 267 5206 1935 1939 glass landscapes review theory http://www.citeulike.org/user/weeks/article/2147206 <i>The European Physical Journal E - Soft Matter, Vol. 18, No. 3. (4 November 2005), pp. 287-293.</i><br /><br />We have studied binary two-dimensional (2D) mixtures of superparamagnetic colloidal particles interacting through magnetic dipole moments, which were induced by an external magnetic field B. By tuning B the effective system temperature could be widely adjusted. Time-dependent particle coordinates measured by video-microscopy provide radial pair-distribution functions, mean-square displacements as well as evidence for heterogeneous dynamics. Characteristic features of 3D glass formers are observed experimentally in 2D for the first time. Experimental realization of a model glass former in 2D H König R Hund K Zahn G Maret doi:10.1140/epje/e2005-00034-9 The European Physical Journal E - Soft Matter, Vol. 18, No. 3. (4 November 2005), pp. 287-293. 2007-12-19T15:56:52-00:00 2005 The European Physical Journal E - Soft Matter 18 3 287 293 2d colloids glass http://www.citeulike.org/user/weeks/article/1513083 <i>Physical Review B, Vol. 43, No. 10. (1 April 1991), pp. 8070-8080.</i><br /><br />We have looked for evidence of a correlation length in a molecular-dynamics simulation of the glass transition. We have studied the correlation functions of both the translational order of particle positions and the orientational order of nearest-neighbor bond angles; and have seen no indication of a diverging length scale. We also present data from the simulation; which extend recent laboratory measurements of the frequency-dependent specific heat and thermal conductivity. Search for a correlation length in a simulation of the glass transition Richard Ernst Sidney Nagel Gary Grest doi:10.1103/PhysRevB.43.8070 Physical Review B, Vol. 43, No. 10. (1 April 1991), pp. 8070-8080. 2007-07-30T15:27:17-00:00 1991 Physical Review B 43 10 8070 8080 American Physical Society glass length-scale simulation structure http://www.citeulike.org/user/weeks/article/1313439 <i>Science, Vol. 267, No. 5206. (31 March 1995), pp. 1924-1935.</i><br /><br />Glasses can be formed by many routes. In some cases, distinct polyamorphic forms are found. The normal mode of glass formation is cooling of a viscous liquid. Liquid behavior during cooling is classified between "strong" and "fragile," and the three canonical characteristics of relaxing liquids are correlated through the fragility. Strong liquids become fragile liquids on compression. In some cases, such conversions occur during cooling by a weak first-order transition. This behavior can be related to the polymorphism in a glass state through a recent simple modification of the van der Waals model for tetrahedrally bonded liquids. The sudden loss of some liquid degrees of freedom through such first-order transitions is suggestive of the polyamorphic transition between native and denatured hydrated proteins, which can be interpreted as single-chain glass-forming polymers plasticized by water and cross-linked by hydrogen bonds. The onset of a sharp change in d<r2>dT(<r2> is the Debye-Waller factor and T is temperature) in proteins, which is controversially indentified with the glass transition in liquids, is shown to be general for glass formers and observable in computer simulations of strong and fragile ionic liquids, where it proves to be close to the experimental glass transition temperature. The latter may originate in strong anharmonicity in modes ("bosons"), which permits the system to access multiple minima of its configuration space. These modes, the Kauzmann temperature TK, and the fragility of the liquid, may thus be connected. 10.1126/science.267.5206.1924 Formation of Glasses from Liquids and Biopolymers CA Angell doi:10.1126/science.267.5206.1924 Science, Vol. 267, No. 5206. (31 March 1995), pp. 1924-1935. 2007-05-20T17:03:13-00:00 1995 Science 267 5206 1924 1935 glass review http://www.citeulike.org/user/weeks/article/733339 <i>J. Phys. Chem. B, Vol. 109, No. 45. (17 November 2005), pp. 21235-21240.</i><br /><br />We perform experiments on two different dense colloidal suspensions with confocal microscopy to probe the relationship between local structure and dynamics near the glass transition. We calculate the Voronoi volume for our particles and show that this quantity is not a universal probe of glassy structure for all colloidal suspensions. We correlate the Voronoi volume to displacement and find that these quantities are only weakly correlated. We observe qualitatively similar results in a simulation of a polymer melt. These results suggest that the Voronoi volume does not predict dynamical behavior in experimental colloidal suspensions; a purely structural approach based on local single particle volume likely cannot describe the colloidal glass transition. Weak Correlations between Local Density and Dynamics near the Glass Transition JC Conrad FW Starr DA Weitz doi:10.1021/jp0514168 J. Phys. Chem. B, Vol. 109, No. 45. (17 November 2005), pp. 21235-21240. 2006-07-03T19:08:55-00:00 2005 J. Phys. Chem. B 109 45 21235 21240 colloids confocal glass pmma structure http://www.citeulike.org/user/weeks/article/1203416 <i>Physical Review Letters, Vol. 89, No. 9. (2002), pp. 095704-095704.</i><br /><br />We use confocal microscopy to study particle motion in colloidal systems. Near the glass transition; motion is inhibited; as particles spend time trapped in transient “cages” formed by neighboring particles. We measure the cage sizes and lifetimes; which; respectively; shrink and grow as the glass transition approaches. Cage rearrangements are more prevalent in regions with lower concentrations and higher disorder. Neighboring rearranging particles typically move in parallel directions; although a nontrivial fraction moves in antiparallel directions; usually from particle pairs with initial separations corresponding to local maxima and minima of the pair correlation function g ( r ); respectively. Properties of Cage Rearrangements Observed near the Colloidal Glass Transition Eric Weeks DA Weitz doi:10.1103/PhysRevLett.89.095704 Physical Review Letters, Vol. 89, No. 9. (2002), pp. 095704-095704. 2007-04-02T22:33:06-00:00 2002 Physical Review Letters 89 9 095704 095704 American Physical Society cages colloids confocal diffusion glass msd pmma http://www.citeulike.org/user/weeks/article/1567407 <i>Physical Review Letters, Vol. 97, No. 26. (2006)</i><br /><br />We use confocal microscopy to visualize individual particles near the colloidal glass transition. We identify the most slowly-relaxing particles and show that they form spatially correlated clusters that percolate across the sample. In supercooled fluids, the largest cluster spans the system on short time scales but breaks up on longer time scales. In contrast, in glasses, a percolating cluster exists on all accessible time scales. Using molecular dynamics simulation, we show that these clusters make the dominant contribution to the bulk elasticity of the sample. Contribution of Slow Clusters to the Bulk Elasticity Near the Colloidal Glass Transition Jacinta Conrad Param Dhillon Eric Weeks David Reichman David Weitz doi:10.1103/PhysRevLett.97.265701 Physical Review Letters, Vol. 97, No. 26. (2006) 2007-08-15T16:26:46-00:00 2006 Physical Review Letters 97 26 APS colloids confocal elasticity glass pmma slow-particles http://www.citeulike.org/user/weeks/article/1605887 <i>Journal of Physics: Condensed Matter, Vol. 19, No. 20. (2007), pp. 205131-205131.</i><br /><br />We use a confocal microscope to examine the motion of individual particles in a dense colloidal suspension. Close to the glass transition, particle motion is strongly spatially correlated. The correlations decay exponentially with particle separation, yielding a dynamic length scale of O(2-3s) (in terms of particle diameter s). This length scale grows modestly as the glass transition is approached. Further, the correlated motion exhibits a strong spatial dependence on the pair correlation function g(r). Motion within glassy samples is weakly correlated, but with a larger spatial scale for this correlation. Short- and long-range correlated motion observed in colloidal glasses and liquids Eric Weeks John Crocker DA Weitz doi:10.1088/0953-8984/19/20/205131 Journal of Physics: Condensed Matter, Vol. 19, No. 20. (2007), pp. 205131-205131. 2007-08-29T17:41:41-00:00 2007 Journal of Physics: Condensed Matter 19 20 205131 205131 colloids confocal glass pmma two-point http://www.citeulike.org/user/weeks/article/1835891 <i>Physica A, Vol. 216, No. 1-2. (1 June 1995), pp. 85-119.</i><br /><br />A systematic theory for the dynamics of hard-sphere suspensions of interacting Brownian particles with both hydrodynamic and direct interactions is presented. A generalized diffusion equation is derived for concentrated suspensions. The volume fraction ([phi]) dependence of the short- and long-time self-diffusion coefficients are thus explored from a unifying point of view. The long-range hydrodynamic interactions due to the Oseen tensor are shown to play a crucial role in both coefficients, while the short-range hydrodynamic interactions just lead to corrections. The importance of the correlation effects between particles due to the long-range hydrodynamic interactions is also stressed. The nonlocal correlation effect is an important factor, leading to the behavior of the long-time self-diffusion coefficient (DSL) as DSL ~ (1 - [phi]/[phi]0)2 near the volume fraction of [phi]0 = 0.5718. The direct interactions are also found to be drastically reduced by the short-range hydrodynamic interactions. On the theory of concentrated hard-sphere suspensions Michio Tokuyama Irwin Oppenheim doi:10.1016/0378-4371(94)00280-7 Physica A, Vol. 216, No. 1-2. (1 June 1995), pp. 85-119. 2007-10-29T15:17:13-00:00 1995 Physica A 216 1-2 85 119 colloids diffusion glass theory http://www.citeulike.org/user/weeks/article/1414541 <i>The Journal of Chemical Physics, Vol. 121, No. 9. (2004), pp. 4237-4245.</i><br /><br />Molecular dynamics simulation and analysis based upon the many-body potential energy landscape (PEL) are employed to characterize single molecule reorientation and structural relaxation, and their interrelation, in deeply supercooled liquid CS2. The rotational mechanism changes from small-step Debye diffusion to sudden large angle reorientation (SLAR) as the temperature falls below the mode-coupling temperature Tc. The onset of SLAR is explained in terms of the PEL; it is an essential feature of low-T rotational dynamics, along with the related phenomena of dynamic heterogeneity and the bifurcation of slow and fast relaxation processes. A long trajectory in which the system is initially trapped in a low energy local minimum, and eventually escapes, is followed in detail, both on the PEL and in real space. During the trapped period, "return" dynamics occurs, always leading back to the trap. Structural relaxation is identified with irreversible escape to a new trap. These processes lead to weak and strong SLAR, respectively; strong SLAR is a clear signal of structural relaxation. Return dynamics involves small groups of two to four molecules, while a string-like structure composed of all the active groups participates in the escape. It is proposed that, rather than simple, nearly instantaneous, one-dimensional barrier crossings, relaxation involves activation of the system to the complex, multidimensional region on the borders of the basins of attraction of the minima for an extended period. ©2004 American Institute of Physics. On the mechanism of reorientational and structural relaxation in supercooled liquids: The role of border dynamics and cooperativity Joohyun Kim T Keyes doi:10.1063/1.1776553 The Journal of Chemical Physics, Vol. 121, No. 9. (2004), pp. 4237-4245. 2007-06-26T21:45:18-00:00 2004 The Journal of Chemical Physics 121 9 4237 4245 AIP dyn-het glass rotation simulation http://www.citeulike.org/user/weeks/article/1454769 <i>Physical Review Letters, Vol. 99, No. 2. (2007), pp. 025702-025702.</i><br /><br />We study a colloidal suspension confined between two quasiparallel walls as a model system for glass transitions in confined geometries. The suspension is a mixture of two particle sizes to prevent wall-induced crystallization. We use confocal microscopy to directly observe the motion of colloidal particles. This motion is slower in confinement, thus producing glassy behavior in a sample which is a liquid in an unconfined geometry. For higher volume fraction samples (closer to the glass transition), the onset of confinement effects occurs at larger length scales. Colloidal Glass Transition Observed in Confinement Carolyn Nugent Kazem Edmond Hetal Patel Eric Weeks doi:10.1103/PhysRevLett.99.025702 Physical Review Letters, Vol. 99, No. 2. (2007), pp. 025702-025702. 2007-07-13T19:38:05-00:00 2007 Physical Review Letters 99 2 025702 025702 APS binary colloids confinement confocal glass goldman msd pmma http://www.citeulike.org/user/weeks/article/1699104 <i>Nature, Vol. 387, No. 6636. (26 June 1997), pp. 883-885.</i> Crystallization of hard-sphere colloids in microgravity Jixiang Zhu Min Li R Rogers W Meyer RH Ottewill Sts-73 WB Russel PM Chaikin Nature, Vol. 387, No. 6636. (26 June 1997), pp. 883-885. 2007-09-27T03:17:26-00:00 1997 Nature 387 6636 883 885 colloids crystals glass gravity journal-club pmma http://www.citeulike.org/user/weeks/article/782016 <i>Physical Review Letters, Vol. 92, No. 25. (2004)</i><br /><br />We perform molecular dynamics simulations to study the structural relaxation dynamics of a model of viscous silica, the prototype of a strong glass former. We find that the melt dynamics are spatially heterogeneous regardless of whether the bulk relaxation is non-Arrhenius or Arrhenius, and cannot be understood as a statistical bondbreaking process. Further, we show that stringlike motion is suppressed by the covalent bondings, yet high particle mobility propagates continuously, supporting the concept of dynamic facilitation emphasized in recent theoretical work. Spatially Heterogeneous Dynamics and Dynamic Facilitation in a Model of Viscous Silica Michael Vogel Sharon Glotzer doi:10.1103/PhysRevLett.92.255901 Physical Review Letters, Vol. 92, No. 25. (2004) 2006-08-01T23:05:33-00:00 2004 Physical Review Letters 92 25 APS facilitation glass journal-club silica simulation http://www.citeulike.org/user/weeks/article/1702300 <i>Physical Review E, Vol. 69, No. 1. (2004), pp. 011505-011505.</i><br /><br />Molecular-dynamics simulations are presented for two correlation functions formed with the partial density fluctuations of binary hard-sphere mixtures in order to explore the effects of mixing on the evolution of glassy dynamics upon compressing the liquid into high-density states. Partial-density-fluctuation correlation functions for the two species are reported. Results for the -relaxation process are quantified by parameters for the strength, stretching, and time scale, where the latter varies over almost four orders of magnitude upon compression. The parameters exhibit an appreciable dependence on the wave vector, and this dependence is different for the correlation function referring to the smaller and that for the larger species. These features are shown to be in semiquantitative agreement with those calculated within the mode-coupling theory for ideal liquid-glass transitions. Alpha-relaxation processes in binary hard-sphere mixtures G Foffi W Götze F Sciortino P Tartaglia T Voigtmann doi:10.1103/PhysRevE.69.011505 Physical Review E, Vol. 69, No. 1. (2004), pp. 011505-011505. 2007-09-27T16:54:56-00:00 2004 Physical Review E 69 1 011505 011505 APS binary glass hard-sphere simulation http://www.citeulike.org/user/weeks/article/1835839 <i>Philosophical Magazine B, Vol. 77, No. 2. (February 1998), pp. 621-631.</i><br /><br />Recent dynamic light scattering measurement on concentrated suspensions of 'hard-sphere' colloidal particles by Segre and Pusey (1996, Phys. Rev. Lett ., 77, 771) are compared with the theoretical results calculated by the coupling model. The calculated normalized intermediate scattering function decays exponentially at both short and long times, f (Q, short t) proportional exp[-DS(Q)Q2t] and f(Q, long t) proportional exp[-DL(Q)Q2t] respectively, with DL(Q) and DS(Q) having the same Q dependence. The ratio DL(Q)/DS(Q) decreases rapidly with volume fraction phi. At intermediate times, the decay of f(Q, t) is slower and nonexponential, becomes increasing slower and extends to longer times as phi increases. There is good agreement between theory and experiment. It is also pointed out that the diffusional dynamics found in concentrated colloidal suspensions are general and shared by other densely packed interacting systems. A coupling model analysis of dynamics of concentrated colloidal suspensions KL Ngai RW Rendell Philosophical Magazine B, Vol. 77, No. 2. (February 1998), pp. 621-631. 2007-10-29T14:52:12-00:00 1998 Philosophical Magazine B 77 2 621 631 colloids diffusion glass theory http://www.citeulike.org/user/weeks/article/1837300 <i>Physical Review Letters, Vol. 85, No. 6. (2000), pp. 1270-1273.</i><br /><br />We show that the structure of the fluctuations close to spinodals and mean-field critical points is qualitatively different from the structure close to non-mean-field critical points. This difference has important implications for many areas including the formation of glasses in supercooled liquids. In particular; the divergence of the measured static structure function in near-mean-field systems close to the glass transition is suppressed relative to the mean-field prediction in systems for which a spatial symmetry is broken. Clusters and Fluctuations at Mean-Field Critical Points and Spinodals W Klein Harvey Gould J Tobochnik FJ Alexander M Anghel Gregory Johnson doi:10.1103/PhysRevLett.85.1270 Physical Review Letters, Vol. 85, No. 6. (2000), pp. 1270-1273. 2007-10-29T21:00:46-00:00 2000 Physical Review Letters 85 6 1270 1273 American Physical Society glass structure theory http://www.citeulike.org/user/weeks/article/1987776 <i>Physical Review Letters, Vol. 75, No. 14. (2 October 1995), pp. 2770-2773.</i><br /><br />The frequency-dependent viscoelastic shear modulus of concentrated suspensions of colloidal hard spheres is shown to be strongly modified as the volume fraction approaches the glass transition. The elastic or storage component; G ′ ; becomes larger than the viscous or loss component; G ′′ . The frequency dependence of G ′ develops a plateau while that of G ′′ develops a minimum. We propose a physical model to account for these data; using a description of the glasslike behavior based on mode-coupling theory; and a description of the high-frequency behavior based on hydrodynamic flow calculations. Linear Viscoelasticity of Colloidal Hard Sphere Suspensions near the Glass Transition TG Mason DA Weitz doi:10.1103/PhysRevLett.75.2770 Physical Review Letters, Vol. 75, No. 14. (2 October 1995), pp. 2770-2773. 2007-11-26T18:16:34-00:00 1995 Physical Review Letters 75 14 2770 2773 American Physical Society colloids glass hard-sphere mct rheology http://www.citeulike.org/user/weeks/article/1678143 <i>Chemical Physics, Vol. 284, No. 1-2. (1 November 2002), pp. 361-367.</i> Subdiffusion and the cage effect studied near the colloidal glass transition Eric Weeks DA Weitz doi:10.1016/S0301-0104(02)00667-5 Chemical Physics, Vol. 284, No. 1-2. (1 November 2002), pp. 361-367. 2007-09-20T04:31:56-00:00 2002 Chemical Physics 284 1-2 361 367 anomalous-diffusion cages colloids confocal glass msd pmma http://www.citeulike.org/user/weeks/article/2184111 <i>EPL (Europhysics Letters), Vol. 49, No. 1. (2000), pp. 68-74.</i><br /><br />We conduct numerical simulations on a simple model of a two-dimensional steady-state sheared foam, and define a quantity G that measures stress fluctuations in the constant-area system. This quantity reduces to the temperature in an equilibrium system. We find that the relation between the viscosity and G is the same as that between viscosity and temperature in a very different system, namely a supercooled liquid. This is the first evidence of a common phenomenon linking these two systems. Sheared foam as a supercooled liquid? SA Langer AJ Liu doi:10.1209/epl/i2000-00121-4 EPL (Europhysics Letters), Vol. 49, No. 1. (2000), pp. 68-74. 2007-12-31T22:52:55-00:00 2000 EPL (Europhysics Letters) 49 1 68 74 2d foam glass jamming simulation http://www.citeulike.org/user/weeks/article/578879 <i>J. Phys. Chem., Vol. 100, No. 31. (1 August 1996), pp. 13200-13212.</i> Supercooled Liquids and Glasses MD Ediger CA Angell SR Nagel doi:10.1021/jp953538d J. Phys. Chem., Vol. 100, No. 31. (1 August 1996), pp. 13200-13212. 2006-04-07T00:58:56-00:00 1996 J. Phys. Chem. 100 31 13200 13212 glass review http://www.citeulike.org/user/weeks/article/1706440 <i>Journal of Non-Crystalline Solids, Vol. 192-193 (2 December 1995), pp. 384-392.</i><br /><br />Scattering experiments studying the dynamics of glass-forming systems have become of special importance for understanding glass transition phenomena. They monitor the density autocorrelation function which has become a key observable since it is calculated within a new concept of the glass transition, the mode coupling theory (MCT). After a short reference to the main predictions and examples of scattering experiments where these phenomena have been observed, results for two model systems will be analyzed with MCT: a recently reported analysis of neutron scattering data for orthoterphenyl in the [beta]-regime is improved and photon correlation spectroscopy data on colloidal spheres are described by simultaneously analyzing the [beta]- and [alpha]-relaxation dynamics using the MCT scaling laws. Scattering experiments for the microscopic understanding of the glass transition E Bartsch doi:10.1016/0022-3093(95)00379-7 Journal of Non-Crystalline Solids, Vol. 192-193 (2 December 1995), pp. 384-392. 2007-09-28T21:17:33-00:00 1995 Journal of Non-Crystalline Solids 192-193 384 392 colloids dls glass mct soft-sphere http://www.citeulike.org/user/weeks/article/1304890 <i>Physica A, Vol. 201, No. 1-3. (1 December 1993), pp. 363-371.</i><br /><br />The collective and single particle dynamics of highly concentrated polystyrene micronetwork spheres of 200 nm diameter as measured by photon correlation spectroscopy (PCS) and forced Rayleigh scattering (FRS), respectively, show the same qualitative features as known for molecular liquids or colloidal suspensions close to the glass transition. A two step decay of the density fluctuations is observed with PCS, which can be quantitatively interpreted by mode coupling theory with a critical volume fraction [phi]c of 0.64. At the same volume fraction a glass transition is indicated independent of any theory through specific changes in the intensity fluctuation pattern. The long time self-diffusion coefficient, as determined by FRS, decreases over about three orders of magnitude in a small volume fraction interval between 0.55 and 0.68. However, traces of ergodicity restoring structure relaxation processes are found even beyond [phi]c = [phi]g. Colloidal polystyrene micronetwork spheres -- a new mesoscopic model of the glass transition in simple liquids E Bartsch V Frenz S Moller H Sillescu doi:10.1016/0378-4371(93)90433-5 Physica A, Vol. 201, No. 1-3. (1 December 1993), pp. 363-371. 2007-05-18T07:14:49-00:00 1993 Physica A 201 1-3 363 371 colloids dls glass soft-sphere http://www.citeulike.org/user/weeks/article/1706390 <i>Physical Review Letters, Vol. 68, No. 24. (15 June 1992), pp. 3646-3649.</i><br /><br />We used diffusing wave spectroscopy to determine the phase diagrams of binary mixtures of charge-stabilized colloidal particles of different dimensions in the low-screening limit. As the ratio of radii r = r 1 / r 2 was increased progressively towards 1; the structure of the diagrams evolved from eutecticlike to azeotropiclike and finally to a diagram where complete solubility was found; much like in atomic systems. We present for the first time evidence for liquid-galss transitions in these strongly interacting systems as the relative composition of both species is varied. Glass transition and phase diagrams of strongly interacting binary colloidal mixtures Amit Meller Joel Stavans doi:10.1103/PhysRevLett.68.3646 Physical Review Letters, Vol. 68, No. 24. (15 June 1992), pp. 3646-3649. 2007-09-28T20:49:28-00:00 1992 Physical Review Letters 68 24 3646 3649 American Physical Society binary colloids dws glass phase-diagram http://www.citeulike.org/user/weeks/article/1409983 <i>The Journal of Chemical Physics, Vol. 125, No. 7. (2006), pp. 074716-074716.</i><br /><br />Coherent anti-Stokes Raman scattering microscopy is performed on glassy systems of poly(methylmethacrylate) colloidal particles in density- and refractive-index-matched solvents. Samples are prepared with varying amounts of linear polystyrene, which induces a depletion driven attraction between the nearly hard-sphere particles. Images collected over several hours confirm the existence of a reentrant glass transition. The images also reveal that the dynamics of repulsive and attractive glasses are qualitatively different. Colloidal particles in repulsive glasses exhibit cage rattling and escape, while those in attractive glasses are nearly static while caged but exhibit large displacements upon (infrequent) cage escape. ©2006 American Institute of Physics Direct imaging of repulsive and attractive colloidal glasses Laura Kaufman David Weitz doi:10.1063/1.2227386 The Journal of Chemical Physics, Vol. 125, No. 7. (2006), pp. 074716-074716. 2007-06-25T01:35:08-00:00 2006 The Journal of Chemical Physics 125 7 074716 074716 AIP colloids depletion glass microscopy http://www.citeulike.org/user/weeks/article/1706356 <i>Physical Review A, Vol. 43, No. 12. (15 June 1991), pp. 6900-6907.</i><br /><br />Static structure factors S ( q ) were measured by laser light scattering for very concentrated systems of spherical; near-monosized; sterically stabilized particles dispersed in nonpolar liquids. A range of systems with particle concentrations beyond that corresponding to the disorder to order transition configurations were found to have amorphous structures. As the particles were stabilized by means of very short chain polymers; these systems were thought to closely approximate the fundamentally important amorphous; hard-sphere system. Subsequent analysis of S ( q ) carried out by means of data generated by the molecular-dynamics method for very concentrated; amorphous states of the hard-sphere system confirmed this interpretation. Thus we were able; by a combination of experiment and simulation; to give an extensive analysis and description of the structure of the amorphous state of a system of hard spheres. This study complements past work on the thermodynamic and transport properties of metastable; amorphous states of a system of hard spheres. Structure of colloidal glasses calculated by the molecular-dynamics method and measured by light scattering I Snook W van Megen P Pusey doi:10.1103/PhysRevA.43.6900 Physical Review A, Vol. 43, No. 12. (15 June 1991), pp. 6900-6907. 2007-09-28T20:36:00-00:00 1991 Physical Review A 43 12 6900 6907 American Physical Society colloids dls glass hard-sphere simulation structure http://www.citeulike.org/user/weeks/article/1840561 <i>Physical Review E, Vol. 69, No. 2. (2004), pp. 020201-020201.</i><br /><br />We numerically obtain a quantitative demonstration that development of spatial correlations of mobility as temperature is lowered is responsible for the "decoupling" of transport properties of supercooled liquids. This result further demonstrates the necessity of a spatial description of the glass formation and therefore seriously challenges a number of popular alternative theoretical descriptions. Time and length scales in supercooled liquids Ludovic Berthier doi:10.1103/PhysRevE.69.020201 Physical Review E, Vol. 69, No. 2. (2004), pp. 020201-020201. 2007-10-30T13:27:13-00:00 2004 Physical Review E 69 2 020201 020201 APS dyn-het glass journal-club lennard-jones http://www.citeulike.org/user/weeks/article/1678090 <i>AIP Conference Proceedings, Vol. 832, No. 1. (2006), pp. 21-25.</i><br /><br />We study concentrated colloidal suspensions, a model system which has a glass transition. The non-equilibrium nature of the glassy state is most clearly highlighted by aging — the dependence of the system's properties on the time elapsed since vitrification. Fast laser scanning confocal microscopy allows us to image a colloidal glass and track the particles in three dimensions. We analyze the static structure in terms of tetrahedral packing. We find that while the aging of the suspension clearly affects its dynamics, none of the geometrical quantities associated with tetrahedra change with age. Invariance of Structure in an Aging Colloidal Glass Gianguido Cianci Rachel Courtland Eric Weeks doi:10.1063/1.2204459 AIP Conference Proceedings, Vol. 832, No. 1. (2006), pp. 21-25. 2007-09-20T04:07:03-00:00 2006 AIP Conference Proceedings 832 1 21 25 AIP aging colloids confocal glass pmma structure tetrahedra http://www.citeulike.org/user/weeks/article/1678088 <i>Solid State Communications, Vol. 139, No. 11-12. (September 2006), pp. 599-604.</i><br /><br />We study concentrated colloidal suspensions, a model system which has a glass transition. Samples in the glassy state show aging, in that the motion of the colloidal particles slows as the sample ages from an initial state. We study the relationship between the static structure and the slowing dynamics, using confocal microscopy to follow the three-dimensional motion of the particles. The structure is quantified by considering tetrahedra formed by quadruplets of neighboring particles. We find that while the sample clearly slows down during aging, the static properties as measured by tetrahedral quantities do not vary. However, a weak correlation between tetrahedron shape and mobility is observed, suggesting that the structure facilitates the motion responsible for the sample aging. Correlations of structure and dynamics in an aging colloidal glass Gianguido Cianci Rachel Courtland Eric Weeks doi:10.1016/j.ssc.2006.04.039 Solid State Communications, Vol. 139, No. 11-12. (September 2006), pp. 599-604. 2007-09-20T04:05:51-00:00 2006 Solid State Communications 139 11-12 599 604 aging colloids confocal glass pmma structure tetrahedra http://www.citeulike.org/user/weeks/article/1676868 <i>Physical Review E, Vol. 59, No. 6. (June 1999), pp. 6824-6829.</i><br /><br />Dynamical and static properties of N =13-4000 hard spheres in spherical cavities with smooth and rough walls have been calculated by molecular-dynamics computer simulations. We use a dynamical criterion to distinguish between fluidlike and solidlike states. The associated crossover densities show a strong dependence both on the system size and on the surface roughness. For large N ; these crossover densities tend to the bulk glass transition density for rough walls and to the bulk crystallization density for smooth walls. The crossover densities for finite N are found to be significantly smaller than the corresponding bulk densities. A detailed examination of the layer-resolved radial- and tangential mean-square displacements reveals qualitatively different dynamics for smooth and rough cavities. Freezing and glass transition of hard spheres in cavities ZT Németh H Löwen doi:10.1103/PhysRevE.59.6824 Physical Review E, Vol. 59, No. 6. (June 1999), pp. 6824-6829. 2007-09-19T18:42:08-00:00 1999 Physical Review E 59 6 6824 6829 American Physical Society confinement glass goldman hard-sphere simulation http://www.citeulike.org/user/weeks/article/1676860 <i>Journal of Applied Physics, Vol. 88, No. 6. (2000), pp. 3113-3157.</i><br /><br />The field of viscous liquid and glassy solid dynamics is reviewed by a process of posing the key questions that need to be answered, and then providing the best answers available to the authors and their advisors at this time. The subject is divided into four parts, three of them dealing with behavior in different domains of temperature with respect to the glass transition temperature, Tg, and a fourth dealing with "short time processes." The first part tackles the high temperature regime T>Tg, in which the system is ergodic and the evolution of the viscous liquid toward the condition at Tg is in focus. The second part deals with the regime T~Tg, where the system is nonergodic except for very long annealing times, hence has time-dependent properties (aging and annealing). The third part discusses behavior when the system is completely frozen with respect to the primary relaxation process but in which secondary processes, particularly those responsible for "superionic" conductivity, and dopart mobility in amorphous silicon, remain active. In the fourth part we focus on the behavior of the system at the crossover between the low frequency vibrational components of the molecular motion and its high frequency relaxational components, paying particular attention to very recent developments in the short time dielectric response and the high Q mechanical response. ©2000 American Institute of Physics. Relaxation in glassforming liquids and amorphous solids CA Angell KL Ngai GB McKenna PF McMillan SW Martin doi:10.1063/1.1286035 Journal of Applied Physics, Vol. 88, No. 6. (2000), pp. 3113-3157. 2007-09-19T18:39:48-00:00 2000 Journal of Applied Physics 88 6 3113 3157 AIP aging glass review http://www.citeulike.org/user/weeks/article/1998181 <i>Nature, Vol. 408, No. 6813. (7 December 2000), pp. 695-698.</i><br /><br />The increasingly sluggish response of a supercooled liquid as it nears its glass transition1 (for example, refrigerated honey) is prototypical of glassy dynamics found in proteins, neural networks and superconductors. The notion that molecules rearrange cooperatively has long been postulated2 to explain diverging relaxation times and broadened (non-exponential) response functions near the glass transition. Recently, cooperativity was observed and analysed in colloid glasses3 and in simulations of binary liquids well above the glass transition4. But nanometre-scale studies of cooperativity at the molecular glass transition are lacking5. Important issues to be resolved include the precise form of the cooperativity and its length scale6, and whether the broadened response is intrinsic to individual cooperative regions, or arises only from heterogeneity7, 8, 9 in an ensemble of such regions. Here we describe direct observations of molecular cooperativity near the glass transition in polyvinylacetate (PVAc), using nanometre-scale probing of dielectric fluctuations. Molecular clusters switched spontaneously among two to four distinct configurations, producing random telegraph noise. Our analysis of these noise signals and their power spectra reveals that individual clusters exhibit transient dynamical heterogeneity and non-exponential kinetics. Direct observation of molecular cooperativity near the glass transition E Vidalrussell NE Israeloff doi:10.1038/35047037 Nature, Vol. 408, No. 6813. (7 December 2000), pp. 695-698. 2007-11-28T00:22:47-00:00 2000 Nature 408 6813 695 698 dyn-het glass http://www.citeulike.org/user/weeks/article/1998069 <i>Journal of Non-Crystalline Solids, Vol. 243, No. 2-3. (February 1999), pp. 81-108.</i><br /><br />Theoretical concepts and experimental evidence of heterogeneity in glass-forming liquids and polymers are reviewed. The main purpose is to provide an introduction to theoretical developments and recent experiments which have led to rapidly increasing knowledge. Realizing that there is no consensus in regard to the various scenarios of the glass transition starting from rather different assumptions we try to give a balanced overview although we also compare and interrelate some of the approaches. The experimental part describes recent nuclear magnetic resonance, dielectric, and optical experiments from which dynamically distinguishable subensembles can be selected thus proving the existence of a well defined dynamical heterogeneity. Heterogeneity at the glass transition: a review Hans Sillescu doi:10.1016/S0022-3093(98)00831-X Journal of Non-Crystalline Solids, Vol. 243, No. 2-3. (February 1999), pp. 81-108. 2007-11-28T00:10:01-00:00 1999 Journal of Non-Crystalline Solids 243 2-3 81 108 dyn-het glass review http://www.citeulike.org/user/weeks/article/2949593 <i>Physical Review E, Vol. 64, No. 4. (2001), 041502.</i> Motions in binary mixtures of hard colloidal spheres: Melting of the glass SR Williams W van Megen doi:10.1103/PhysRevE.64.041502 Physical Review E, Vol. 64, No. 4. (2001), 041502. 2008-07-02T00:48:53-00:00 2001 Physical Review E 64 4 041502 American Physical Society binary dls glass http://www.citeulike.org/user/weeks/article/1994877 <i>Physical Review Letters, Vol. 90, No. 17. (2 May 2003), 175702.</i><br /><br />Broadband dielectric measurements were carried out on di- n -butyl phthalate (DBP) under isothermal conditions at hydrostatic pressures up to 1.6 GPa. A comparison of the dielectric relaxation times with the viscosity revealed that no breakdown of the Einstein-Debye relation is induced by high compression. This absence of any decoupling is attributed to the weak intermolecular cooperativity of DBP and its negligible change with pressure. Because of the latter; the dielectric spectra conform to time-pressure superpositioning. Test of the Einstein-Debye Relation in Supercooled Dibutylphthalate at Pressures up to 1.4 GPa M Paluch M Sekula S Pawlus SJ Rzoska J Ziolo CM Roland doi:10.1103/PhysRevLett.90.175702 Physical Review Letters, Vol. 90, No. 17. (2 May 2003), 175702. 2007-11-27T16:27:10-00:00 2003 Physical Review Letters 90 17 175702 American Physical Society diffusion glass pressure rotation http://www.citeulike.org/user/weeks/article/1875708 <i>Physical Review Letters, Vol. 81, No. 20. (16 November 1998), 4404.</i><br /><br />Using molecular dynamics computer simulations we investigate how the relaxation dynamics of a simple supercooled liquid with Newtonian dynamics differs from the one with a stochastic dynamics. We find that; apart from the early β-relaxation regime; the two dynamics give rise to the same relaxation behavior. The increase of the relaxation times of the system upon cooling; the details of the α relaxation; as well as the wave-vector dependence of the Edwards-Anderson parameters; are independent of the microscopic dynamics. How Does the Relaxation of a Supercooled Liquid Depend on Its Microscopic Dynamics? Tobias Gleim Walter Kob Kurt Binder doi:10.1103/PhysRevLett.81.4404 Physical Review Letters, Vol. 81, No. 20. (16 November 1998), 4404. 2007-11-07T00:33:45-00:00 1998 Physical Review Letters 81 20 4404 American Physical Society brownian-motion glass simulation http://www.citeulike.org/user/weeks/article/1300604 <i>Physical Review E, Vol. 53, No. 3. (March 1996), pp. 2995-2997.</i><br /><br />We discuss several aspects of the fluidized domain model advanced earlier to explain rotational and translational diffusion rates for fragile glass formers and; in particular; we point out weaknesses in the preceding Comment [Sillescu; Phys. Rev. E 53 ; 2992 (1996)]. Recent experimental results are cited to refine estimates of domain characteristics for orthoterphenyl at T g and to suggest that domain heterogeneity in space and time underlies stretched exponential relaxation behavior for rotational motion. © 1996 The American Physical Society. Reply to “Comment on `Translation-rotation paradox for diffusion in fragile glass-forming liquids' ” Frank Stillinger Jennifer Hodgdon doi:10.1103/PhysRevE.53.2995 Physical Review E, Vol. 53, No. 3. (March 1996), pp. 2995-2997. 2007-05-16T17:50:04-00:00 1996 Physical Review E 53 3 2995 2997 American Physical Society controversy diffusion glass rotation http://www.citeulike.org/user/weeks/article/1836362 <i>Nat Mater, Vol. 2, No. 10. (October 2003), pp. 695-700.</i><br /><br />Despite the decade-long study of the effect of nanoconfinement on the glass-transition temperature (Tg) of amorphous materials, the quest to probe the distribution of Tgs in nanoconfined glass formers has remained unfulfilled. Here the distribution of Tgs across polystyrene films has been obtained by a fluorescence/multilayer method, revealing that the enhancement of dynamics at a surface affects Tg several tens of nanometres into the film. The extent to which dynamics smoothly transition from enhanced to bulk states depends strongly on nanoconfinement. When polymer films are sufficiently thin that a reduction in thickness leads to a reduction in overall Tg, the surface-layer Tg actually increases with a reduction in overall thickness, whereas the substrate-layer Tg decreases. These results indicate that the gradient in Tg dynamics is not abrupt, and that the size of a cooperatively rearranging region is much smaller than the distance over which interfacial effects propagate. The distribution of glass-transition temperatures in nanoscopically confined glass formers Christopher Ellison John Torkelson doi:10.1038/nmat980 Nat Mater, Vol. 2, No. 10. (October 2003), pp. 695-700. 2007-10-29T17:55:32-00:00 2003 Nat Mater 2 10 695 700 confinement glass journal-club polymer http://www.citeulike.org/user/weeks/article/2909079 <i>Physical Review Letters, Vol. 95, No. 7. (2005)</i><br /><br />A theoretical approach is developed to derive a hierarchy of mode-coupling equations for the dynamics of concentrated colloidal suspensions, which improves the prediction of the colloidal glass transition. Our derivation is based on a matrix formalism for stochastic dynamics and the resulting recursive expressions for irreducible memory functions. The 1st order truncation of the generalized mode-coupling closure recovers mode-coupling theory, whereas its 2nd and 3rd order truncations provide corrections. The predictions of the transition volume fraction and Debye-Waller parameter for the hard-sphere colloidal system improve with the increasing mode-coupling order and compare favorably with experimental measurements. High-Order Mode-Coupling Theory for the Colloidal Glass Transition Jianlan Wu Jianshu Cao doi:10.1103/PhysRevLett.95.078301 Physical Review Letters, Vol. 95, No. 7. (2005) 2008-06-19T23:08:11-00:00 2005 Physical Review Letters 95 7 APS colloids glass mct http://www.citeulike.org/user/weeks/article/1702049 <i>Physica A: Statistical and Theoretical Physics, Vol. 233, No. 1-2. (15 November 1996), pp. 102-116.</i><br /><br />Phase behaviour, crystallisation kinetics and particle dynamics are compared for two colloidal suspensions of hard spherical particles with different particle size distributions; one is narrow and roughly symmetrical and the other is broader and skewed towards smaller particles. Both suspensions exhibit the equilibrium phase behaviour expected for a system of identical hard spheres and they show a glass transition, indicated by the cessation of homogeneous nucleation and the partial arrest of concentration fluctuations, at approximately the same volume fraction, [Phi]g [approximate] 0.58. Interestingly, compared to the suspension with the narrower size distribution, crystallisation rates are significantly slower in the more polydisperse suspension. In its colloidal glass state no crystal growth occurs on secondary nuclei, such as the shear-aligned crystals that can be induced in both suspensions by regular rocking. Effect of particle size distribution on crystallisation and the glass transition of hard sphere colloids SI Henderson TC Mortensen SM Underwood W van Megen doi:10.1016/S0378-4371(96)00153-7 Physica A: Statistical and Theoretical Physics, Vol. 233, No. 1-2. (15 November 1996), pp. 102-116. 2007-09-27T16:45:30-00:00 1996 Physica A: Statistical and Theoretical Physics 233 1-2 102 116 colloids crystals dls glass polydisperse http://www.citeulike.org/user/weeks/article/1300601 <i>Physical Review E, Vol. 53, No. 3. (March 1996), pp. 2992-2994.</i><br /><br />F. H. Stillinger and J. A. Hodgdon [Phys. Rev. E 50 ; 2064 (1994)] have proposed a ‘‘fluidized domain’’ model to explain that the diffusion coefficient ratio D trans / D rot increases by a factor of ∼10 2 on approaching the glass transition from above in fragile liquids. In their numerical estimates they make ad hoc assumptions that lead to a very small volume fraction φ 0 ∼10 -5 of the fluidized domains. It is shown how these assumptions can be avoided and φ 0 ∼10 -1 results from experimental values of D trans ; D rot ; and the width of the D rot distribution. A modification of the Stillinger-Hodgdon model can be derived from the two-state model of Beckert and Pfeifer [Ann. Phys. (Leipzig) 16 ; 262 (1965)] and yields experimental estimates of a few nanometers for the fluidized domains. © 1996 The American Physical Society. Comment on `Translation-rotation paradox for diffusion in fragile glass-forming liquids' Hans Sillescu doi:10.1103/PhysRevE.53.2992 Physical Review E, Vol. 53, No. 3. (March 1996), pp. 2992-2994. 2007-05-16T17:46:28-00:00 1996 Physical Review E 53 3 2992 2994 American Physical Society controversy diffusion glass rotation http://www.citeulike.org/user/weeks/article/2902937 <i>Journal of Physics: Condensed Matter, Vol. 20, No. 24. (2008), 244128.</i><br /><br />The local deformation of two-dimensional Lennard-Jones glasses under imposed shear strain is studied via computer simulations. Both the mean squared displacement and mean squared strain rise linearly with the length of the strain interval Dg over which they are measured. However, the increase in displacement does not represent single-particle diffusion. There are long-range spatial correlations in displacement associated with slip lines with an amplitude of order the particle size. Strong dependence on system size is also observed. The probability distributions of displacement and strain are very different. For small Dg the distribution of displacement has a plateau followed by an exponential tail. The distribution becomes Gaussian as Dg increases to about 0.03. The strain distributions consist of sharp central peaks associated with elastic regions, and long exponential tails associated with plastic regions. The latter persist to the largest Dg studied. Evolution of displacements and strains in sheared amorphous solids Craig Maloney Mark Robbins doi:10.1088/0953-8984/20/24/244128 Journal of Physics: Condensed Matter, Vol. 20, No. 24. (2008), 244128. 2008-06-17T18:09:23-00:00 2008 Journal of Physics: Condensed Matter 20 24 244128 glass lennard-jones shear simulation http://www.citeulike.org/user/weeks/article/1836349 <i>Science, Vol. 309, No. 5733. (15 July 2005), pp. 456-459.</i><br /><br />We analyzed the glassy-state structural relaxation of polymers near surfaces and interfaces by monitoring fluorescence in multilayer films. Relative to that of bulk, the rate of structural relaxation of poly(methyl methacrylate) is reduced by a factor of 2 at a free surface and by a factor of 15 at a silica substrate interface; the latter exhibits a nearly complete arresting of relaxation. The distribution in relaxation rates extends more than 100 nanometers into the film interior, a distance greater than that over which surfaces and interfaces affect the glass transition temperature. 10.1126/science.1112217 Structural Relaxation of Polymer Glasses at Surfaces, Interfaces, and In Between Rodney Priestley Christopher Ellison Linda Broadbelt John Torkelson doi:10.1126/science.1112217 Science, Vol. 309, No. 5733. (15 July 2005), pp. 456-459. 2007-10-29T17:51:36-00:00 2005 Science 309 5733 456 459 confinement glass polymer http://www.citeulike.org/user/weeks/article/1305100 <i>Physical Review Letters, Vol. 86, No. 1. (1 January 2001), 111.</i><br /><br />We calculate the distribution of interparticle normal forces P ( F ) near the glass and jamming transitions in model supercooled liquids and foams; respectively. P ( F ) develops a peak that appears near the glass or jamming transitions; whose height increases with decreasing temperature; decreasing shear stress and increasing packing density. A similar shape of P ( F ) was observed in experiments on static granular packings. We propose that the appearance of this peak signals the development of a yield stress. The sensitivity of the peak to temperature; shear stress; and density lends credence to the recently proposed generalized jamming phase diagram. Force Distributions near Jamming and Glass Transitions Corey O'Hern Stephen Langer Andrea Liu Sidney Nagel doi:10.1103/PhysRevLett.86.111 Physical Review Letters, Vol. 86, No. 1. (1 January 2001), 111. 2007-05-18T10:36:37-00:00 2001 Physical Review Letters 86 1 111 American Physical Society foam force-chain glass jamming simulation http://www.citeulike.org/user/weeks/article/1303281 <i>The Journal of Chemical Physics, Vol. 101, No. 3. (1994), pp. 2391-2397.</i><br /><br />We present a continuum theory of frustration-limited clusters in one-component glass-forming liquids that accounts, in part, for the recently reported [Fischer et al., J. Non-Cryst. Solids, 131–133, 134 (1991)], and quite unexpected, presence in simple glass-forming liquids of stable clusters at low temperatures (T) and the even less expected persistence for very long times of these clusters at higher T's. The model is based on the idea that there is a local structure that is energetically preferred over simple crystalline packing, which is strained (frustrated) over large distances; although in a curved space the preferred packing could lead to “ideal” crystallization at temperatures that are usually above the actual freezing temperature, in “flat” space this transition is narrowly avoided. We are led to a new ansatz for the T dependence of the viscosity, which permits us to collapse data for many liquids onto a universal curve. The Journal of Chemical Physics is copyrighted by The American Institute of Physics. Frustration-limited clusters in liquids Steven Kivelson Xiaolin Zhao Daniel Kivelson Thomas Fischer Charles Knobler doi:10.1063/1.468414 The Journal of Chemical Physics, Vol. 101, No. 3. (1994), pp. 2391-2397. 2007-05-17T16:43:03-00:00 1994 The Journal of Chemical Physics 101 3 2391 2397 AIP glass structure theory