TY - JOUR

T1 - Visualization of the collective vortex-like motions in liquid argon and water

T2 - Molecular dynamics simulation

AU - Anikeenko, A. V.

AU - Malenkov, G. G.

AU - Naberukhin, Yu I.

PY - 2018/3/7

Y1 - 2018/3/7

N2 - We propose a new measure of collectivity of molecular motion in the liquid: the average vector of displacement of the particles, <ΔR>, which initially have been localized within a sphere of radius Rsph and then have executed the diffusive motion during a time interval Δt. The more correlated the motion of the particles is, the longer will be the vector <ΔR>. We visualize the picture of collective motions in molecular dynamics (MD) models of liquids by constructing the <ΔR> vectors and pinning them to the sites of the uniform grid which divides each of the edges of the model box into equal parts. MD models of liquid argon and water have been studied by this method. Qualitatively, the patterns of <ΔR> vectors are similar for these two liquids but differ in minor details. The most important result of our research is the revealing of the aggregates of <ΔR> vectors which have the form of extended flows which sometimes look like the parts of vortices. These vortex-like clusters of <ΔR> vectors have the mesoscopic size (of the order of 10 nm) and persist for tens of picoseconds. Dependence of the <ΔR> vector field on parameters Rsph, Δt, and on the model size has been investigated. This field in the models of liquids differs essentially from that in a random-walk model.

AB - We propose a new measure of collectivity of molecular motion in the liquid: the average vector of displacement of the particles, <ΔR>, which initially have been localized within a sphere of radius Rsph and then have executed the diffusive motion during a time interval Δt. The more correlated the motion of the particles is, the longer will be the vector <ΔR>. We visualize the picture of collective motions in molecular dynamics (MD) models of liquids by constructing the <ΔR> vectors and pinning them to the sites of the uniform grid which divides each of the edges of the model box into equal parts. MD models of liquid argon and water have been studied by this method. Qualitatively, the patterns of <ΔR> vectors are similar for these two liquids but differ in minor details. The most important result of our research is the revealing of the aggregates of <ΔR> vectors which have the form of extended flows which sometimes look like the parts of vortices. These vortex-like clusters of <ΔR> vectors have the mesoscopic size (of the order of 10 nm) and persist for tens of picoseconds. Dependence of the <ΔR> vector field on parameters Rsph, Δt, and on the model size has been investigated. This field in the models of liquids differs essentially from that in a random-walk model.

KW - VELOCITY AUTOCORRELATION FUNCTION

KW - LONG-TIME CORRELATIONS

KW - COMPUTER-MODELS

KW - SPATIAL CORRELATIONS

KW - TERM CORRELATIONS

KW - GLASS-TRANSITION

KW - DIFFUSIVE MOTION

KW - LARGE-SCALE

KW - ATOMS

KW - HETEROGENEITY

UR - http://www.scopus.com/inward/record.url?scp=85043465677&partnerID=8YFLogxK

U2 - 10.1063/1.5018140

DO - 10.1063/1.5018140

M3 - Article

AN - SCOPUS:85043465677

VL - 148

JO - Journal of Chemical Physics

JF - Journal of Chemical Physics

SN - 0021-9606

IS - 9

M1 - 094508

ER -