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Title: Nature of self-diffusion in two-dimensional fluids

Self-diffusion in a two-dimensional simple fluid is investigated by both analytical and numerical means. We investigate the anomalous aspects of self-diffusion in two-dimensional fluids with regards to the mean square displacement, the time-dependent diffusion coefficient, and the velocity autocorrelation function (VACF) using a consistency equation relating these quantities. Here, we numerically confirm the consistency equation by extensive molecular dynamics simulations for finite systems, corroborate earlier results indicating that the kinematic viscosity approaches a finite, non-vanishing value in the thermodynamic limit, and establish the finite size behavior of the diffusion coefficient. We obtain the exact solution of the consistency equation in the thermodynamic limit and use this solution to determine the large time asymptotics of the mean square displacement, the diffusion coefficient, and the VACF. An asymptotic decay law of the VACF resembles the previously known self-consistent form, 1/($$t\sqrt{In t)}$$ however with a rescaled time.
Authors:
 [1] ;  [1] ;  [2] ;  [3] ;  [4] ; ORCiD logo [1]
  1. Korea Advanced Inst. Science and Technology (KAIST), Daejeon (Korea, Republic of). Dept. of Chemistry
  2. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Computational Research Division
  3. Univ. Augsburg, Augsburg (Germany). Inst. fur Physik
  4. Yokohama City Univ., Yokohama (Japan). Graduate School of Medical Life Science
Publication Date:
Grant/Contract Number:
AC02-05CH11231; A0702001005; SC0008271
Type:
Published Article
Journal Name:
New Journal of Physics
Additional Journal Information:
Journal Volume: 19; Journal Issue: 12; Related Information: © 2017 The Author(s). Published by IOP Publishing Ltd on behalf of Deutsche Physikalische Gesellschaft.; Journal ID: ISSN 1367-2630
Publisher:
IOP Publishing
Research Org:
Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
Sponsoring Org:
USDOE Office of Science (SC), Advanced Scientific Computing Research (ASCR) (SC-21); Korea Advanced Institute of Science and Technology (KAIST)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY; 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; 97 MATHEMATICS AND COMPUTING; self-diffusion; long-time tail; anomalous diffusion; molecular dynamics simulation; consistency equation
OSTI Identifier:
1437764
Alternate Identifier(s):
OSTI ID: 1432222