Time Scales of Fickian Diffusion and the Lifetime of Dynamic Heterogeneity
Dynamic heterogeneity, believed to be one of the hallmarks of the dynamics of supercooled liquids, is expected to affect the diffusion of the particles comprising the liquid. We have carried out extensive molecular dynamics simulations of two model glass forming liquids in three dimensions to study...
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| Format: | Article |
| Language: | English |
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Frontiers Media S.A.
2020-07-01
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| Series: | Frontiers in Physics |
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| Online Access: | https://www.frontiersin.org/article/10.3389/fphy.2020.00210/full |
| _version_ | 1818842071746740224 |
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| author | Rajsekhar Das Chandan Dasgupta Chandan Dasgupta Smarajit Karmakar |
| author_facet | Rajsekhar Das Chandan Dasgupta Chandan Dasgupta Smarajit Karmakar |
| author_sort | Rajsekhar Das |
| collection | DOAJ |
| description | Dynamic heterogeneity, believed to be one of the hallmarks of the dynamics of supercooled liquids, is expected to affect the diffusion of the particles comprising the liquid. We have carried out extensive molecular dynamics simulations of two model glass forming liquids in three dimensions to study the time scales at which Fick's law of diffusion starts to set in. We have identified two different Fickian time scales: one at which the mean squared displacement begins to show a linear dependence on time, and another one at which the distribution of particle displacements becomes Gaussian. These two times scales are found to be very different from each other and from the α relaxation time in both systems. An interesting connection is found between one of these Fickian time scales and the time scale obtained from the bond-breakage correlation function. We discuss the relation among these different time scales and their connection to dynamic heterogeneity in the system. |
| first_indexed | 2024-12-19T04:36:09Z |
| format | Article |
| id | doaj.art-b50e26b350264b00953822b5d58a3b7a |
| institution | Directory Open Access Journal |
| issn | 2296-424X |
| language | English |
| last_indexed | 2024-12-19T04:36:09Z |
| publishDate | 2020-07-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Physics |
| spelling | doaj.art-b50e26b350264b00953822b5d58a3b7a2022-12-21T20:35:44ZengFrontiers Media S.A.Frontiers in Physics2296-424X2020-07-01810.3389/fphy.2020.00210521902Time Scales of Fickian Diffusion and the Lifetime of Dynamic HeterogeneityRajsekhar Das0Chandan Dasgupta1Chandan Dasgupta2Smarajit Karmakar3Tata Institute of Fundamental Research, Hyderabad, IndiaCentre for Condensed Matter Theory, Department of Physics, Indian Institute of Science, Bangalore, IndiaInternational Centre for Theoretical Sciences, Bangalore, IndiaTata Institute of Fundamental Research, Hyderabad, IndiaDynamic heterogeneity, believed to be one of the hallmarks of the dynamics of supercooled liquids, is expected to affect the diffusion of the particles comprising the liquid. We have carried out extensive molecular dynamics simulations of two model glass forming liquids in three dimensions to study the time scales at which Fick's law of diffusion starts to set in. We have identified two different Fickian time scales: one at which the mean squared displacement begins to show a linear dependence on time, and another one at which the distribution of particle displacements becomes Gaussian. These two times scales are found to be very different from each other and from the α relaxation time in both systems. An interesting connection is found between one of these Fickian time scales and the time scale obtained from the bond-breakage correlation function. We discuss the relation among these different time scales and their connection to dynamic heterogeneity in the system.https://www.frontiersin.org/article/10.3389/fphy.2020.00210/fullsupercooled liquidFickian and non-Fickian behaviorsglass transitionvan Hove correlation functiondynamic heterogeneities |
| spellingShingle | Rajsekhar Das Chandan Dasgupta Chandan Dasgupta Smarajit Karmakar Time Scales of Fickian Diffusion and the Lifetime of Dynamic Heterogeneity Frontiers in Physics supercooled liquid Fickian and non-Fickian behaviors glass transition van Hove correlation function dynamic heterogeneities |
| title | Time Scales of Fickian Diffusion and the Lifetime of Dynamic Heterogeneity |
| title_full | Time Scales of Fickian Diffusion and the Lifetime of Dynamic Heterogeneity |
| title_fullStr | Time Scales of Fickian Diffusion and the Lifetime of Dynamic Heterogeneity |
| title_full_unstemmed | Time Scales of Fickian Diffusion and the Lifetime of Dynamic Heterogeneity |
| title_short | Time Scales of Fickian Diffusion and the Lifetime of Dynamic Heterogeneity |
| title_sort | time scales of fickian diffusion and the lifetime of dynamic heterogeneity |
| topic | supercooled liquid Fickian and non-Fickian behaviors glass transition van Hove correlation function dynamic heterogeneities |
| url | https://www.frontiersin.org/article/10.3389/fphy.2020.00210/full |
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