Efficient Parallel Decomposition of Dynamical Sampling in Glass-Forming Materials Based on an “On the Fly” Definition of Metabasins

Tsalikis, Dimitrios G.; Lempesis, Nikolaos; Boulougouris, Georgios C.; Theodorou, Doros N.

doi:10.1021/ct9004245

Cited by 14 publications

(65 citation statements)

References 71 publications

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“…These long distance transitions correspond to collective rearrangements, whereas short distance transitions correspond to isolated cage-breaking events. It has been proposed to use this methodology to identify metabasins "on the fly" during parallel microcanonical molecular dynamics simulations [183]. This model has been superimposed onto a network model (see section 5.5) of the PEL in order to simulate aging dynamics [184].…”

Section: Activated Dynamicsmentioning

confidence: 99%

Computer simulations of glasses: the potential energy landscape

Raza

Alling

Abrikosov

2015

J. Phys.: Condens. Matter

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Abstract. We review the current state of research on glasses, discussing the theoretical background and computational models employed to describe them. This article focuses on the use of the potential energy landscape (PEL) paradigm to account for the phenomenology of glassy systems, and the way in which it can be applied in simulations and the interpretation of their results. This article provides a broad overview of the rich phenomenology of glasses, followed by a summary of the theoretical frameworks developed to describe this phenomonology. We discuss the background of the PEL in detail, the onerous task of how to generate computer models of glasses, various methods of analysing numerical simulations, and the literature on the most commonly used model systems. Finally, we tackle the problem of how to distinguish a good glass former from a good crystal former from an analysis of the PEL. In summarising the state of the potential energy landscape picture, we develop the foundations for new theoretical methods that allow the ab initio prediction of the glass-forming ability of new materials by analysis of the PEL.

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Section: Activated Dynamicsmentioning

confidence: 99%

Computer simulations of glasses: the potential energy landscape

Raza

Alling

Abrikosov

2015

J. Phys.: Condens. Matter

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“…22,23 All the above applications constitute clear evidence that a better understanding of the PEL's structure can lead to useful physical conclusions, providing insight into complex mechanisms such as cage breaking events and string motion in atomic systems. [24][25][26] The depth, number, and overall geometry of the basins surrounding the potential energy minima play a dominant role when attempting to describe a PEL in detail. 27 Additionally, inherent structures communicate with each other via transitions; at low temperatures, many of these transitions are rare events, their rate constants being governed by firstorder saddle points on the multidimensional hypersurface between the basins.…”

Section: Introductionmentioning

confidence: 99%

“…Following the pioneering work of Heuer, 28 Bouchaud, 29 and Kob, 30 we will refer to a collection of relatively fast communicating basins as a "metabasin" (MB). Metabasins can be identified "on the fly" in the course of a MD simulation as described in the work of Tsalikis et al 24 In that work, a highly parallelizable scheme is proposed for the calculation of transition rates between communicating basins by following a swarm of microcanonical MD trajectories. Based on the rate of identifying new, not already visited, basins, MBs are defined in the course of a canonical MD run.…”

Section: Introductionmentioning

confidence: 99%

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Temporal disconnectivity of the energy landscape in glassy systems

Lempesis

Boulougouris

Theodorou

2013

The Journal of Chemical Physics

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An alternative graphical representation of the potential energy landscape (PEL) has been developed and applied to a binary Lennard-Jones glassy system, providing insight into the unique topology of the system's potential energy hypersurface. With the help of this representation one is able to monitor the different explored basins of the PEL, as well as how--and mainly when--subsets of basins communicate with each other via transitions in such a way that details of the prior temporal history have been erased, i.e., local equilibration between the basins in each subset has been achieved. In this way, apart from detailed information about the structure of the PEL, the system's temporal evolution on the PEL is described. In order to gather all necessary information about the identities of two or more basins that are connected with each other, we consider two different approaches. The first one is based on consideration of the time needed for two basins to mutually equilibrate their populations according to the transition rate between them, in the absence of any effect induced by the rest of the landscape. The second approach is based on an analytical solution of the master equation that explicitly takes into account the entire explored landscape. It is shown that both approaches lead to the same result concerning the topology of the PEL and dynamical evolution on it. Moreover, a "temporal disconnectivity graph" is introduced to represent a lumped system stemming from the initial one. The lumped system is obtained via a specially designed algorithm [N. Lempesis, D. G. Tsalikis, G. C. Boulougouris, and D. N. Theodorou, J. Chem. Phys. 135, 204507 (2011)]. The temporal disconnectivity graph provides useful information about both the lumped and the initial systems, including the definition of "metabasins" as collections of basins that communicate with each other via transitions that are fast relative to the observation time. Finally, the two examined approaches are compared to an "on the fly" molecular dynamics-based algorithm [D. G. Tsalikis, N. Lempesis, G. C. Boulougouris, and D. N. Theodorou, J. Chem. Theory Comput. 6, 1307 (2010)].

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“…[7] Small time durations of the molecular dynamics (MD) simulation, the non-equilibrated polymer chains, the restricted portion of the configurational space that is explored, are some of the factors that affect the final computed output. [3,8,9] Obtaining relaxed amorphous configurations is in fact a central problem for the simulation of polymers. The original breakthrough was achieved by Theodorou and Suter.…”

Section: Introductionmentioning

confidence: 99%

Effect of the Molar Volume on the Elastic Properties of Vinylic Polymers: A Static Molecular Modeling Approach

Metatla

Soldera

2011

Macro Theory & Simulations

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The effect of the molar volume on the mechanical properties of three polymers is computed using molecular mechanics. It is demonstrated that elastic properties significantly depend on the molar volume. To be reproducible they must be determined for a series of “stable” glassy configurations for which the potential energy is minimized not only according to the coordinates but also to the molar volume. If these conditions are not fulfilled, a great disparity in values between experiment and simulation is observed. The procedure is first applied to PVC. It is then argued that coherent results stemming from the application of this approach to both tacticities of PMMA justifies its application toward other polymers. magnified image

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Efficient Parallel Decomposition of Dynamical Sampling in Glass-Forming Materials Based on an “On the Fly” Definition of Metabasins

Cited by 14 publications

References 71 publications

Computer simulations of glasses: the potential energy landscape

Computer simulations of glasses: the potential energy landscape

Temporal disconnectivity of the energy landscape in glassy systems

Effect of the Molar Volume on the Elastic Properties of Vinylic Polymers: A Static Molecular Modeling Approach

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