β relaxation in a highly supercooled state via molecular dynamics simulation

Muranaka, Tadashi; Hiwatari, Yasuaki

doi:10.1103/physreve.51.r2735

Cited by 96 publications

(104 citation statements)

References 17 publications

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“…that the system has a heterogeneous dynamics. Recently the answer to the question of dynamic heterogeneity has been addressed both by means of experiments [5][6][7] and computer simulations of two-dimensional [8][9][10] and three-dimensional systems [11][12][13][14][15][16]. Here we study a binary Lennard-Jones mixture in three dimensions which has been investigated before extensively [15] and which shows clear dynamic heterogeneity above the glass transition.…”

Section: Introductionmentioning

confidence: 99%

Dynamical heterogeneities below the glass transition

Vollmayr-Lee

Kob

Binder

et al. 2002

The Journal of Chemical Physics

111

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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 fluctuation around its average position. The 5% particles with the largest/smallest mean amplitude are thus defined as the relatively most mobile/immobile particles. We investigate for these 5% particles their spatial distribution and find them to be distributed very heterogeneously in that mobile as well as immobile particles form clusters. The reason for this dynamic heterogeneity is traced back to the fact that mobile/immobile particles are surrounded by fewer/more neighbors which form an effectively wider/narrower cage. The dependence of our results on the length of the simulation run indicates that individual particles have a characteristic mobility time scale, which can be approximated via the non-Gaussian parameter.02.70. Ns, 61.20.Lc, 61.43.Fs,

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Section: Introductionmentioning

confidence: 99%

Dynamical heterogeneities below the glass transition

Vollmayr-Lee

Kob

Binder

et al. 2002

The Journal of Chemical Physics

111

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“…However, there have been a number of recent computational investigations addressing these issues. For example, Muranaka and Hiwatari [2] showed that displacements of particles measured over a timescale of the order of 5 collision times are correlated within a range of about two interparticle distances in a two-dimensional binary mixture of soft disks below the freezing point. Wahnström [29] showed that hopping processes in a strongly supercooled binary mixture are cooperative in nature.…”

Section: Introductionmentioning

confidence: 99%

“…As a consequence, computer simulations of supercooled liquids, in which this microscopic information is immediately available, are increasingly used to complement theoretical and experimental efforts. In particular, simulations in recent years have focused on the study of "dynamical heterogeneity" to understand the microscopic origin of slow dynamics and stretched exponential relaxation in glass-forming liquids [2][3][4][5][6].…”

Section: Introductionmentioning

confidence: 99%

Spatial correlations of mobility and immobility in a glass-forming Lennard-Jones liquid

et al. 1999

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Using extensive molecular dynamics simulations of an equilibrium, glass-forming Lennard-Jones mixture, we characterize in detail the local atomic motions. We show that spatial correlations exist among particles undergoing extremely large ("mobile") or extremely small ("immobile") displacements over a suitably chosen time interval. The immobile particles form the cores of relatively compact clusters, while the mobile particles move cooperatively and form quasi-one-dimensional, string-like clusters. The strength and length scale of the correlations between mobile particles are found to grow strongly with decreasing temperature, and the mean cluster size appears to diverge at the mode-coupling critical temperature. We show that these correlations in the particle displacements are related to equilibrium fluctuations in the local potential energy and local composition.

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“…We refer to a system as dynamically heterogeneous if it is possible to select a dynamically distinguishable subset of particles by experiment or computer simulation [20]. Simulations [21,22,23,24,25,26,27] and experiments [28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43] have demonstrated the cooperative and spatially heterogeneous nature of the liquid dynamics (for reviews of the experimental evidence for spatially heterogeneous dynamics, see, e. g., Refs. [44,45,46]).…”

Section: Introductionmentioning

confidence: 99%

Dynamical Heterogeneity and Jamming in Glass-Forming Liquids

Lacevic

Glotzer

2004

J. Phys. Chem. B

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The relationship between spatially heterogeneous dynamics (SHD) and jamming is studied in a glass-forming binary Lennard-Jones system via molecular dynamics simulations. It has been suggested by O'Hern et al. [1] that the probability distribution of interparticle forces P (F ) develops a peak at the glass transition temperature Tg, and that the large force inhomogeneities, responsible for structural arrest in granular materials, are related to dynamical heterogeneities in supercooled liquids that form glasses. It has been further suggested that "force chains" present in granular materials may exist in supercooled liquids, and may provide an order parameter for the glass transition. Our goal is to investigate the extent to which the forces experienced by particles in a glass-forming liquid are related to SHD, and compare these forces to those observed in granular materials and other glass-forming systems. Our results are summarized as follows. We find no peak in P (F ) at any temperature in our system, even below Tg. We also find that particles that have been localized for a long time are less likely to experience high relative force and that mobile particles experience higher relative forces at shorter time scales, indicating a correlation between pairwise forces and particle mobility. We construct force chains based on the magnitude of pairwise forces. We find that force chains constructed in this manner are composed of both localized and mobile particles, therefore there is no one-to-one correspondence between force chains as defined here and locally mobile or immobile regions of the liquid. We also find that force chains do not play the same role as force chains in granular materials, but may indicate a difference in the evolution of the local environment of particles with different mobility. We also discuss a possible relationship between force chains found here and the development of string-like motion found in other glass-forming liquids [2,3].

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β relaxation in a highly supercooled state via molecular dynamics simulation

Cited by 96 publications

References 17 publications

Dynamical heterogeneities below the glass transition

Dynamical heterogeneities below the glass transition

Spatial correlations of mobility and immobility in a glass-forming Lennard-Jones liquid

Dynamical Heterogeneity and Jamming in Glass-Forming Liquids

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