Walter Kob

Glass transitions in 1, 2, 3, and 4 dimensional binary Lennard-Jones systems (2008)

Brüning, Ralf, St-Onge, Denis A., Patterson, Steve, Kob, Walter

We investigate the calorimetric liquid-glass transition by performing simulations of a binary Lennard-Jones mixture in one through four dimensions. Starting at a high temperature, the systems are...

Static and dynamic properties of a reversible gel (2008)

Hurtado, Pablo I., Chaudhuri, Pinaki, Berthier, Ludovic, Kob, Walter

We study a microscopically realistic model of a physical gel and use computer simulations to investigate its static and dynamic properties at thermal equilibrium. The phase diagram comprises a sol...

On the relaxation dynamics of glass-forming systems: Insights from computer simulations (2008)

Chaudhuri, Pinaki, Berthier, Ludovic, Sastry, Srikanth, Kob, Walter

We discuss the relaxation dynamics of a simple lattice gas model for glass-forming systems and show that with increasing density of particles this dynamics slows down very quickly. By monitoring the...

A genetic algorithm for the atomistic design and global optimisation of substitutionally disordered materials (2008)

Mohn, Chris E., Kob, Walter

We present a genetic algorithm for the atomistic design and global optimisation of substitutionally disordered bulk materials and surfaces. Premature convergence which hamper conventional genetic...

Coupling/decoupling between translational and rotational dynamics in a supercooled molecular liquid (2008)

Chong, Song-Ho, Kob, Walter

We use molecular dynamics computer simulations to investigate the coupling between translational and rotational dynamics in a glass-forming liquid of dumbbells. We find that, if characterized by the...

Tracking heterogeneous dynamics during the alpha-relaxation of a simple glass-former (2008)

Chaudhuri, Pinaki, Sastry, Srikanth, Kob, Walter

We study the relaxation process in a simple glass-former, viz. the KA lattice gas model. We show that for this model structural relaxation is caused by the slow percolation of regions of particles...

New fitting scheme to obtain effective potential from Car-Parrinello molecular dynamics simulations: Application to silica (2008)

Carre, Antoine, Horbach, Juergen, Ispas, Simona, Kob, Walter

A fitting scheme is proposed to obtain effective potentials from Car-Parrinello molecular dynamics (CPMD) simulations. It is used to parameterize a new pair potential for silica. MD simulations with...

New fitting scheme to obtain effective potential from Car-Parrinello molecular dynamics simulations: Application to silica (2008)

Carre, Antoine, Horbach, Jürgen, Ispas, Simona, Kob, Walter

A fitting scheme is proposed to obtain effective potentials from Car-Parrinello molecular dynamics (CPMD) simulations. It is used to parameterize a new pair potential for silica. MD simulations with...

A random walk description of the heterogeneous glassy dynamics of attracting colloids (2007)

Chaudhuri, Pinaki, Gao, Yongxiang, Berthier, Ludovic, Kilfoil, Maria, Kob, Walter

We study the heterogeneous dynamics of attractive colloidal particles close to the gel transition using confocal microscopy experiments combined with a theoretical statistical analysis. We focus on...

Amorphous silica modeled with truncated and screened Coulomb interactions: A molecular dynamics simulation study (2007)

Carre, Antoine, Berthier, Ludovic, Horbach, Jürgen, Ispas, Simona, Kob, Walter

We show that finite-range alternatives to the standard long-range pair potential for silica by van Beest et al. [Phys. Rev. Lett. 64, 1955 (1990)] might be used in molecular dynamics simulations. We...

Universal nature of particle displacements close to glass and jamming transitions (2007)

Chaudhuri, Pinaki, Berthier, Ludovic, Kob, Walter

We examine the structure of the distribution of single particle displacements (van-Hove function) in a broad class of materials close to glass and jamming transitions. In a wide time window...

Amorphous silica modeled with truncated and screened Coulomb interactions: A molecular dynamics simulation study (2007)

Carré, Antoine, Berthier, Ludovic, Horbach, Juergen, Ispas, Simona, Kob, Walter

We show that finite-range alternatives to the standard long-range BKS pair potential for silica might be used in molecular dynamics simulations. We study two such models that can be efficiently...

Structure and dynamics of l-Ge: Neutron scattering experiments and ab initio molecular dynamics simulations (2007)

Hugouvieux, Virginie, Farhi, Emmanuel, Johnson, Mark R., Juranyi, Fanni, Bourges, Philippe, Kob, Walter

We report the first measurements of the dynamics of liquid germanium (l-Ge) by quasi-elastic neutron scattering on time-of-flight and triple-axis spectrometers. These results are compared with...

First-principles molecular-dynamics simulations of a hydrous silica melt: Structural properties and hydrogen diffusion mechanism (2007)

Poehlmann, Markus, Benoit, Magali, Kob, Walter

We use {\it ab initio} molecular dynamics simulations to study a sample of liquid silica containing 3.84 wt.% H$_2$O.We find that, for temperatures of 3000 K and 3500 K,water is almost exclusively...

Heterogeneous diffusion in a reversible gel (2006)

Hurtado, Pablo I., Berthier, Ludovic, Kob, Walter

We introduce a microscopically realistic model of a physical gel and use computer simulations to study its static and dynamic properties at thermal equilibrium. The phase diagram comprises a sol...

The relaxation dynamics of a supercooled liquid confined by rough walls (2006)

Scheidler, Peter, Kob, Walter, Binder, Kurt

We present the results of molecular dynamics computer simulations of a binary Lennard-Jones liquid confined between two parallel rough walls. These walls are realized by frozen amorphous...

Cooperative motion and growing length scales in supercooled confined liquids (2006)

Scheidler, Peter, Kob, Walter, Binder, Kurt

Using molecular dynamics simulations we investigate the relaxation dynamics of a supercooled liquid close to a rough as well as close to a smooth wall. For the former situation the relaxation times...

Growing length scales in a supercooled liquid close to an interface (2006)

Scheidler, Peter, Kob, Walter, Binder, Kurt, Parisi, Giorgio

We present the results of molecular dynamics computer simulations of a simple glass former close to an interface between the liquid and the frozen amorphous phase of the same material. By...

The Monte-Carlo dynamics of a binary Lennard-Jones glass-forming mixture (2006)

Berthier, Ludovic, Kob, Walter

We use a standard Monte-Carlo algorithm to study the slow dynamics of a binary Lennard-Jones glass-forming mixture at low temperature. We find that Monte-Carlo is by far the most efficient way to...

Spontaneous and induced dynamic fluctuations in glass-formers I: General results and dependence on ensemble and dynamics (2006)

Berthier, Ludovic, Biroli, Giulio, Bouchaud, Jean-Philippe, Kob, Walter, Miyazaki, Kunimasa, Reichman, David

We study theoretically and numerically a family of multi-point dynamic susceptibilities that quantify the strength and characteristic lengthscales of dynamic heterogeneities in glass-forming...

Spontaneous and induced dynamic correlations in glass-formers II: Model calculations and comparison to numerical simulations (2006)

Berthier, Ludovic, Biroli, Giulio, Bouchaud, Jean-Philippe, Kob, Walter, Miyazaki, Kunimasa, Reichman, David

We study in detail the predictions of various theoretical approaches, in particular mode-coupling theory (MCT) and kinetically constrained models (KCMs), concerning the time, temperature, and...

Dynamics of a rod in a homogeneous/inhomogeneous frozen disordered medium: Correlation functions and non-Gaussian effects (2006)

Moreno, Angel J., Kob, Walter

We present molecular dynamics simulations of the motion of a single rigid rod in a disordered static 2d-array of disk-like obstacles. Two different configurations have been used for the latter: A...

Structure and diffusion in amorphous aluminium silicate: A molecular dynamics computer simulation (2005)

Winkler, Anke, Horbach, Jurgen, Kob, Walter, Binder, Kurt

The amorphous aluminium silicate (Al2O3)2(SiO2) [AS2] is investigated by means of large scale molecular dynamics computer simulations. We consider fully equilibrated melts in the temperature range...

Water adsorption on amorphous silica surfaces: A Car-Parrinello simulation study (2005)

Mischler, Claus, Horbach, Juergen, Kob, Walter, Binder, Kurt

A combination of classical molecular dynamics (MD) and ab initio Car-Parrinello molecular dynamics (CPMD) simulations is used to investigate the adsorption of water on a free amorphous silica...

Structure and Relaxation Dynamics of a Colloidal Gel (2005)

Del Gado, Emanuela, Kob, Walter

Using molecular dynamics computer simulations we investigate the structural and dynamical properties of a simple model for a colloidal gel at low volume fraction. We find that at low T the system is...

Water adsorption on amorphous silica surfaces: A Car-Parrinello simulation study (2005)

Mischler, Claus, Horbach, Juergen, Kob, Walter, Binder, Kurt

A combination of classical molecular dynamics (MD) and ab initio Car-Parrinello molecular dynamics (CPMD) simulations is used to investigate the adsorption of water on a free amorphous silica...

Dynamics in a supercooled liquid of symmetric dumbbells: Reorientational hopping for small molecular elongations (2005)

Moreno, Angel J., Chong, Song-Ho, Kob, Walter, Sciortino, Francesco

We present extensive molecular dynamics simulations of a liquid of symmetric dumbbells, for constant packing fraction, as a function of temperature and molecular elongation. For large elongations,...

Water adsorption on amorphous silica surfaces: A Car-Parrinello simulation study (2005)

Mischler, Claus, Horbach, Juergen, Kob, Walter, Binder, Kurt

A combination of classical molecular dynamics (MD) and ab initio Car-Parrinello molecular dynamics (CPMD) simulations is used to investigate the adsorption of water on a free amorphous silica...

Water adsorption on amorphous silica surfaces: A Car-Parrinello simulation study (2005)

Mischler, Claus, Horbach, Juergen, Kob, Walter, Binder, Kurt

A combination of classical molecular dynamics (MD) and ab initio Car-Parrinello molecular dynamics (CPMD) simulations is used to investigate the adsorption of water on a free amorphous silica...

First-principles molecular-dynamics simulations of a hydrous silica melt: Structural properties and hydrogen diffusion mechanism (2004)

Poehlmann, Markus, Benoit, Magali, Kob, Walter

We use {\it ab initio} molecular dynamics simulations to study a sample of liquid silica containing 3.84 wt.% H$_2$O.We find that, for temperatures of 3000 K and 3500 K,water is almost exclusively...

Structural properties of a calcium aluminosilicate glass from molecular-dynamics simulations: A finite size effects study (2004)

Ganster, Patrick, Benoit, Magali, Kob, Walter, Delaye, Jean-Marc

We study a calcium aluminosilicate glass of composition (SiO$_2$)$_{0.67}$-(Al$_2$O$_3$)$_{0.12}$-(CaO)$_{0.21}$ by means of molecular-dynamics (MD) simulations, using a potential made of two-body...

Relaxation dynamics of a linear molecule in a random static medium: A scaling analysis (2004)

Moreno, Angel J., Kob, Walter

We present extensive molecular dynamics simulations of the motion of a single linear rigid molecule in a two-dimensional random array of fixed obstacles. The diffusion constant for the center of mass...

Dynamics of a Rigid Rod in a Glassy Medium (2003)

Moreno, Angel J., Kob, Walter

We present simulations of the motion of a single rigid rod in a disordered static 2d-array of disk-like obstacles. The rotational, $D_{\rm R}$, and center-of-mass translational, $D_{\rm CM}$,...

The relaxation dynamics of a supercooled liquid confined by rough walls (2003)

Scheidler, Peter, Kob, Walter, Binder, Kurt

We present the results of molecular dynamics computer simulations of a binary Lennard-Jones liquid confined between two parallel rough walls. These walls are realized by frozen amorphous...

Molecular Dynamics Simulations (2003)

Binder, Kurt, Horbach, Jurgen, Kob, Walter, Paul, Wolfgang, Varnik, Fathollah

A tutorial introduction to the technique of Molecular Dynamics (MD) is given, and some characteristic examples of applications are described. The purpose and scope of these simulations and the...

Amorphous silica at surfaces and interfaces: simulation studies (2003)

Horbach, Juergen, Stuehn, Torsten, Mischler, Claus, Kob, Walter, Binder, Kurt

The structure of surfaces and interfaces of silica (SiO2) is investigated by large scale molecular dynamics computer simulations. In the case of a free silica surface, the results of a classical...

Structure and diffusion in amorphous aluminium silicate: A molecular dynamics computer simulation (2003)

Winkler, Anke, Horbach, Jurgen, Kob, Walter, Binder, Kurt

The amorphous aluminium silicate (Al2O3)2(SiO2) [AS2] is investigated by means of large scale molecular dynamics computer simulations. We consider fully equilibrated melts in the temperature range...

Structure and diffusion in amorphous aluminium silicate: A molecular dynamics computer simulation (2003)

Winkler, Anke, Horbach, Jurgen, Kob, Walter, Binder, Kurt

The amorphous aluminium silicate (Al2O3)2(SiO2) [AS2] is investigated by means of large scale molecular dynamics computer simulations. We consider fully equilibrated melts in the temperature range...

Structure and diffusion in amorphous aluminium silicate: A molecular dynamics computer simulation (2003)

Winkler, Anke, Horbach, Jurgen, Kob, Walter, Binder, Kurt

The amorphous aluminium silicate (Al2O3)2(SiO2) [AS2] is investigated by means of large scale molecular dynamics computer simulations. We consider fully equilibrated melts in the temperature range...

Supercooled liquids, the glass transition, and computer simulations (2002)

Kob, Walter

Lecture notes for LES HOUCHES 2002 SUMMER SCHOOL - SESSION LXXVII on SLOW RELAXATIONS AND NONEQUILIBRIUM DYNAMICS IN CONDENSED MATTER; Les Houches: July 1-26, 2002

Statics and dynamics of the ten-state nearest-neighbor Potts glass on the simple-cubic lattice (2002)

Brangian, Claudio, Kob, Walter, Binder, Kurt

We present the results of Monte Carlo simulations of two different Potts glass models with short range random interactions. In the first model a \pm J-distribution of the bonds is chosen, in the...

The vibrational dynamics of vitreous silica: Classical force fields vs. first-principles (2002)

Benoit, Magali, Kob, Walter

We compare the vibrational properties of model SiO_2 glasses generated by molecular-dynamics simulations using the effective force field of van Beest et al. (BKS) with those obtained when the BKS...

Numerical Investigations of the Glass Transition and Glassy State of Structural Glasses and Spin Glasses (2002)

Horst Rollnik, Dietrich Wolf (editors, Kurt Binder, J Urgen Horbach, Walter Kob

Model for the Structural Glass Transition? For the model of SiO 2 in Sec. 2, the lowest temperature that could be simulated in thermal equilibrium was T = 2750 K, while the experimental glass...

The structural relaxation of molten sodium disilicate (2002)

Horbach, Jurgen, Kob, Walter

We use molecular dynamics computer simulations to study the relaxation dynamics of Na2O-2(SiO2) in its molten, highly viscous state. We find that at low temperatures the incoherent intermediate...

Cooperative motion and growing length scales in supercooled confined liquids (2002)

Scheidler, Peter, Kob, Walter, Binder, Kurt

Using molecular dynamics simulations we investigate the relaxation dynamics of a supercooled liquid close to a rough as well as close to a smooth wall. For the former situation the relaxation times...

Simulation of models for the glass transition: Is there progress? (2002)

Binder, Kurt, Baschnagel, Jörg, Kob, Walter, Paul, Wolfgang

The glass transition of supercooled fluids is a particular challenge for computer simulation, because the (longest) relaxation times increase by about 15 decades upon approaching the transition...

Evidence against a glass transition in the 10-state short range Potts glass (2002)

Brangian, Claudio, Kob, Walter, Binder, Kurt

We present the results of Monte Carlo simulations of two different 10-state Potts glasses with random nearest neighbor interactions on a simple cubic lattice. In the first model the interactions come...

The dynamics of sodium in sodium disilicate: Channel relaxation and sodium diffusion (2001)

Horbach, Juergen, Kob, Walter, Binder, Kurt

We use molecular dynamics computer simulations to study the dynamics of amorphous (Na_2O)2(SiO_2). We find that the Na ions move in channels embedded in a SiO_2 matrix. The characteristic distance...

Dynamical Heterogeneities Below the Glass Transition (2001)

Vollmayr-Lee, Katharina, Kob, Walter, Binder, Kurt, Zippelius, Annette

We present molecular dynamics simulations of a binary Lennard-Jones mixture at temperatures below the kinetic glass transition. The ``mobility'' of a particle is characterized by the amplitude of its...

Quantitative tests of mode-coupling theory for fragile and strong glass-formers (2001)

Kob, Walter, Nauroth, Markus, Sciortino, Francesco

We calculate for a binary mixture of Lennard-Jones particles the time dependence of the solution of the mode-coupling equations in which the full wave vector dependence is taken into account. In...

Classical and ab initio molecular dynamic simulation of an amorphous silica surface (2001)

Mischler, Claus, Kob, Walter, Binder, Kurt

We present the results of a classical molecular dynamic simulation as well as of an ab initio molecular dynamic simulation of an amorphous silica surface. In the case of the classical simulation we...

Statics and Dynamics of the 10-state mean-field Potts glass model: A Monte Carlo study (2001)

Brangian, Claudio, Kob, Walter, Binder, Kurt

We investigate by means of Monte Carlo simulations the fully connected p-state Potts model for different system sizes in order to see how the static and dynamic properties of a finite model compare...

Growing length scales in a supercooled liquid close to an interface (2001)

Scheidler, Peter, Kob, Walter, Binder, Kurt, Parisi, Giorgio

We present the results of molecular dynamics computer simulations of a simple glass former close to an interface between the liquid and the frozen amorphous phase of the same material. By...

The High Temperature Dynamics of a mean field Potts glass (2001)

Brangian, Claudio, Kob, Walter, Binder, Kurt

We use Monte Carlo simulations to investigate the dynamical properties of the infinite range 10 states Potts glass. By analyzing the spin autocorrelation function for system sizes up to N=2560, we...

The relaxation dynamics of a viscous silica melt: II The intermediate scattering functions (2001)

Horbach, Jurgen, Kob, Walter

We use molecular dynamics computer simulations to study the relaxation dynamics of a viscous melt of silica. The coherent and incoherent intermediate scattering functions, F_d(q,t) and F_s(q,t), show...

Channel diffusion of sodium in a silicate glass (2001)

Jund, Philippe, Kob, Walter, Jullien, Remi

We use classical molecular dynamics simulations to study the dynamics of sodium atoms in amorphous Na$_2$O-4SiO$_2$. We find that the sodium trajectories form a well connected network of pockets and...

Structure and Dynamics of amorphous Silica Surfaces (2000)

Roder, Alexandra, Kob, Walter, Binder, Kurt

We use molecular dynamics computer simulations to study the equilibrium properties of the surface of amorphous silica. Two types of geometries are investigated: i) clusters with different diameters...

Finite-size scaling at the dynamical transition of the mean-field 10-state Potts glass (2000)

Brangian, Claudio, Kob, Walter, Binder, Kurt

We use Monte Carlo simulations to study the static and dynamical properties of a Potts glass with infinite range Gaussian distributed exchange interactions for a broad range of temperature and system...

The Debye-Waller factor of liquid silica: Theory and simulation (2000)

Sciortino, Francesco, Kob, Walter

We show that the prediction of mode-coupling theory for a model of a network-forming strong glass-former correctly describes the wave-vector dependence of the Debye-Waller factor. To obtain a good...

Frequency dependent specific heat of viscous silica (2000)

Scheidler, Peter, Kob, Walter, Latz, Arnulf, Horbach, Jurgen, Binder, Kurt

We apply the Mori-Zwanzig projection operator formalism to obtain an expression for the frequency dependent specific heat c(z) of a liquid. By using an exact transformation formula due to Lebowitz et...

The entrance dynamics of polymers into a gel (2000)

Kob, Walter, Cugliandolo, Leticia F.

We use computer simulations to study the (driven) dynamics of a charged polymer in a disordered medium, thus mimicking the setting used in gel electrophoresis. In agreement with experiments, we find...

Equilibrating Glassy Systems with Parallel Tempering (2000)

Kob, Walter, Brangian, Claudio, Stuhn, Torsten, Yamamoto, Ryoichi

We discuss the efficiency of the so-called parallel tempering method to equilibrate glassy systems also at low temperatures. The main focus is on two structural glass models, SiO_2 and a...

The relaxation dynamics of a simple glass former confined in a pore (2000)

Scheidler, Peter, Kob, Walter, Binder, Kurt

We use molecular dynamics computer simulations to investigate the relaxation dynamics of a binary Lennard-Jones liquid confined in a narrow pore. We find that the average dynamics is strongly...

Static and dynamical properties of a supercooled liquid confined in a pore (2000)

Scheidler, Peter, Kob, Walter, Binder, Kurt

We present the results of a Molecular Dynamics computer simulation of a binary Lennard-Jones liquid confined in a narrow pore. The surface of the pore has an amorphous structure similar to that of...

Replica-exchange molecular dynamics simulation for supercooled liquids (2000)

Yamamoto, Ryoichi, Kob, Walter

We investigate to what extend the replica-exchange Monte Carlo method is able to equilibrate a simple liquid in its supercooled state. We find that this method does indeed allow to generate...

Supercooled Liquids and Glasses (1999)

Kob, Walter

In these lectures, which were presented at "Soft and Fragile Matter, Nonequilibrium Dynamics, Metastability and Flow" University of St. Andrews, 8 July - 22 July, 1999, I give an introduction to the...

Structural and dynamical properties of sodium silicate melts: An investigation by molecular dynamics computer simulation (1999)

Horbach, Jurgen, Kob, Walter, Binder, Kurt

We present the results of large scale computer simulations in which we investigate the static and dynamic properties of sodium disilicate and sodium trisilicate melts. We study in detail the static...

Aging in a simple glassformer (1999)

Kob, Walter, Barrat, Jean-Louis, Sciortino, Francesco, Tartaglia, Piero

Using molecular dynamics computer simulations we investigate the out-of-equilibrium dynamics of a Lennard-Jones system after a quench from a high temperature to one below the glass transition...

High Frequency Dynamics of Amorphous Silica (1999)

Horbach, Jurgen, Kob, Walter, Binder, Kurt

We present the results of extensive molecular dynamics computer simulations in which the high frequency dynamics of silica, nu>0.5 THz, is investigated in the viscous liquid state as well as in the...

Aging in a Simple Glassformer (1999)

Walter Kob, Jean-louis Barrat, Francesco Sciortino

. Using molecular dynamics computer simulations we investigate the outof -equilibrium dynamics of a Lennard-Jones system after a quench from a high temperature to one below the glass transition...

Fluctuations, response and aging dynamics in a simple glass-forming liquid out of equilibrium (1999)

Kob, Walter, Barrat, Jean-Louis

By means of molecular dynamics computer simulations we investigate the out of equilibrium relaxation dynamics of a simple glass former, a binary Lennard-Jones system, after a quench to low...

Aging as dynamics in configuration space (1999)

Kob, Walter, Sciortino, Francesco, Tartaglia, Piero

The relaxation dynamics of many disordered systems, such as structural glasses, proteins, granular materials or spin glasses, is not completely frozen even at very low temperatures. This residual...

The Structure and Dynamics of Sodium Disilicate (1999)

Horbach, Jurgen, Kob, Walter

We investigate the structure and dynamics of sodium disilicate by means of molecular dynamics computer simulation. We show that the structure is described by a partially destroyed tetrahedral SiO_4...

The beta-relaxation dynamics of a simple liquid (1999)

Gleim, Tobias, Kob, Walter

We present a detailed analysis of the beta-relaxation dynamics of a simple glass former, a Lennard-Jones system with a stochastic dynamics. By testing the various predictions of mode-coupling theory,...

The Boson Peak in Amorphous Silica: Results from Molecular Dynamics Computer Simulations (1999)

Horbach, Jurgen, Kob, Walter, Binder, Kurt

We investigate a prominent vibrational feature in amorphous silica, the so-called boson peak, by means of molecular dynamics computer simulations. The dynamic structure factor S(q,nu) in the liquid,...

Frequency Dependent Specific Heat of Amorphous Silica: A Molecular Dynamics Computer Simulation (1999)

Scheidler, Peter, Kob, Walter, Horbach, Jurgen, Binder, Kurt

We use molecular dynamics computer simulations to calculate the frequency dependence of the specific heat of a SiO_2 melt. The ions interact with the BKS potential and the simulations are done in the...

Static and Dynamic Properties of a Viscous Silica Melt Molecular Dynamics Computer Simulations (1999)

Horbach, Jurgen, Kob, Walter

We present the results of a large scale molecular dynamics computer simulation in which we investigated the static and dynamic properties of a silica melt in the temperature range in which the...