Understanding the phenomenon of viscous slowing down of glass-forming liquids from the static pair correlation function

Singh, Ankit; Singh, Yashwant

doi:10.48550/arxiv.1909.02734

Cited by 2 publications

(3 citation statements)

References 15 publications

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“…(3.2) to calculate βE (s) at different temperatures and then use these values in Eqs. (2.8-2.10) to calculate values of ψ(T ) and n (s) (T ) [38]. The plot of n (s) (T ) + 1 vs 1/S c (T ) in Fig.…”

Section: Discussionmentioning

confidence: 99%

Emergence of cooperatively reorganizing cluster and super-Arrhenius dynamics of fragile supercooled liquids

Singh,

Bhattacharyya,

Singh

2020

Preprint

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In this paper we develop a theory to calculate the structural relaxation time τα of fragile supercooled liquids. Using the information of the configurational entropy and structure we calculate the number of dynamically free, metastable, and stable neighbors around a central particle. In supercooled liquids the cooperatively reorganizing clusters (CRCs) in which the stable neighbors form "stable" nonchemical bonds with the central particle emerge. For an event of relaxation to take place these bonds have to reorganize irreversibly; the energy involved in the processes is the effective activation energy of relaxation. The theory brings forth a temperature Ta and a temperature dependent parameter ψ(T ) which characterize slowing down of dynamics on cooling. It is shown that the value of ψ(T ) is equal to 1 for T > Ta indicating that the underlying microscopic mechanism of relaxation is dominated by the entropy driven processes while for T < Ta, ψ(T ) decreases on cooling indicating the emergence of the energy driven processes. This crossover of ψ(T ) from high to low temperatures explains the crossover seen in τα. The dynamics of systems that may have similar static structure but very different dynamics can be understood in terms of ψ(T ). We present results for the Kob-Anderson model for three densities and show that the calculated values of τα are in excellent agreement with simulation values for all densities. We also show that when ψ(T ), τα and other quantities are plotted as a function of T /Ta (or Ta/T ) the data collapse on master curves.

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Section: Discussionmentioning

confidence: 99%

Emergence of cooperatively reorganizing cluster and super-Arrhenius dynamics of fragile supercooled liquids

Singh,

Bhattacharyya,

Singh

2020

Preprint

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“…This is achieved by including momentum distribution in the definition of g(r) and using information of the configurational entropy S c . The g(r) of a binary mixture written in the centerof-mass coordinates is [1][2][3],…”

Section: Theorymentioning

confidence: 99%

“…In previous papers [1][2][3] of this series we introduced a new theory for slowing down of dynamics of fragile liquids on cooling. The theory identifies the local structural order that defines the cooperativity of relaxation and brings forth a temperature T a and a temperature dependent parameter ψ(T ) that characterize temperature and density dependence of structural relaxation time.…”

Section: Introductionmentioning

confidence: 99%

How attractive and repulsive interactions affect structure ordering and dynamics of glass-forming liquids?

Singh,

Singh

2021

Preprint

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The theory developed in our previous papers is applied in this paper to investigate the dependence of slowing down of dynamics of glass-forming liquids on the attractive and repulsive parts of intermolecular interactions. Through an extensive comparison of the behavior of a Lennard-Jones glass-forming liquid and that of its WCA reduction to a model with truncated pair potential without attractive tail, we demonstrate why the two systems exhibit very different dynamics despite having nearly identical pair correlation functions. In particular, we show that local structures characterized by number of mobile and immobile particles around a central particle markedly differ in the two systems at densities and temperatures where their dynamics show large difference and nearly identical where dynamics nearly overlap. We also show how the parameter ψ(T ) that measures the role of fluctuations embedded in the system on size of the cooperatively reorganizing cluster (CRC) and the crossover temperature Ta depend on the intermolecular interactions. These parameters stemming from the intermolecular interactions characterize the temperature and density dependence of structural relaxation time τα. The quantitative and qualitative agreements found with simulation results for the two systems suggest that our theory brings out the underlying features that determine dynamics of glass-forming liquids.

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Understanding the phenomenon of viscous slowing down of glass-forming liquids from the static pair correlation function

Cited by 2 publications

References 15 publications

Emergence of cooperatively reorganizing cluster and super-Arrhenius dynamics of fragile supercooled liquids

Emergence of cooperatively reorganizing cluster and super-Arrhenius dynamics of fragile supercooled liquids

How attractive and repulsive interactions affect structure ordering and dynamics of glass-forming liquids?

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