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Title: Role of density modulation in the spatially resolved dynamics of strongly confined liquids

Abstract

Confinement by walls usually produces a strong modulation in the density of dense liquids near the walls. Using molecular dynamics simulations, we examine the effects of the density modulation on the spatially resolved dynamics of a liquid confined between two parallel walls, using a resolution of a fraction of the interparticle distance in the liquid. The local dynamics is quantified by the relaxation time associated with the temporal autocorrelation function of the local density. We find that this local relaxation time varies in phase with the density modulation. The amplitude of the spatial modulation of the relaxation time can be quite large, depending on the characteristics of the wall and thermodynamic parameters of the liquid. To disentangle the effects of confinement and density modulation on the spatially resolved dynamics, we compare the dynamics of a confined liquid with that of an unconfined one in which a similar density modulation is induced by an external potential. We find several differences indicating that density modulation alone cannot account for all the features seen in the spatially resolved dynamics of confined liquids. We also examine how the dynamics near a wall depends on the separation between the two walls and show that themore » features seen in our simulations persist in the limit of large wall separation.« less

Authors:
;  [1]
  1. Centre for Condensed Matter Theory, Department of Physics, Indian Institute of Science, Bangalore 560012 (India)
Publication Date:
OSTI Identifier:
22679037
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Chemical Physics; Journal Volume: 145; Journal Issue: 5; Other Information: (c) 2016 Author(s); Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; DENSITY; LIQUIDS; MODULATION; MOLECULAR DYNAMICS METHOD; RELAXATION TIME

Citation Formats

Saw, Shibu, E-mail: shibu.saw@sydney.edu.au, and Dasgupta, Chandan, E-mail: cdgupta@physics.iisc.ernet.in. Role of density modulation in the spatially resolved dynamics of strongly confined liquids. United States: N. p., 2016. Web. doi:10.1063/1.4959942.
Saw, Shibu, E-mail: shibu.saw@sydney.edu.au, & Dasgupta, Chandan, E-mail: cdgupta@physics.iisc.ernet.in. Role of density modulation in the spatially resolved dynamics of strongly confined liquids. United States. doi:10.1063/1.4959942.
Saw, Shibu, E-mail: shibu.saw@sydney.edu.au, and Dasgupta, Chandan, E-mail: cdgupta@physics.iisc.ernet.in. Sun . "Role of density modulation in the spatially resolved dynamics of strongly confined liquids". United States. doi:10.1063/1.4959942.
@article{osti_22679037,
title = {Role of density modulation in the spatially resolved dynamics of strongly confined liquids},
author = {Saw, Shibu, E-mail: shibu.saw@sydney.edu.au and Dasgupta, Chandan, E-mail: cdgupta@physics.iisc.ernet.in},
abstractNote = {Confinement by walls usually produces a strong modulation in the density of dense liquids near the walls. Using molecular dynamics simulations, we examine the effects of the density modulation on the spatially resolved dynamics of a liquid confined between two parallel walls, using a resolution of a fraction of the interparticle distance in the liquid. The local dynamics is quantified by the relaxation time associated with the temporal autocorrelation function of the local density. We find that this local relaxation time varies in phase with the density modulation. The amplitude of the spatial modulation of the relaxation time can be quite large, depending on the characteristics of the wall and thermodynamic parameters of the liquid. To disentangle the effects of confinement and density modulation on the spatially resolved dynamics, we compare the dynamics of a confined liquid with that of an unconfined one in which a similar density modulation is induced by an external potential. We find several differences indicating that density modulation alone cannot account for all the features seen in the spatially resolved dynamics of confined liquids. We also examine how the dynamics near a wall depends on the separation between the two walls and show that the features seen in our simulations persist in the limit of large wall separation.},
doi = {10.1063/1.4959942},
journal = {Journal of Chemical Physics},
number = 5,
volume = 145,
place = {United States},
year = {Sun Aug 07 00:00:00 EDT 2016},
month = {Sun Aug 07 00:00:00 EDT 2016}
}