Statistics of small length scale density fluctuations in supercooled viscous liquids

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Abstract

Many successful theories of liquids near the melting temperature assume that small length scale density fluctuations follow Gaus­sian statistics. This paper presents a numerical investigation of density fluctuations in the supercooled viscous regime using an enhanced sampling method. Five model systems are investigated: the single component Lennard-Jones liquid, the Kob-Andersen binary mixture, the Wahnstrom binary mixture, the Lewis-Wahnstrom model of ortho-terphenyl, and the TIP4P /Ice model of water. The results show that the Gaussian approximation persists to a good degree into the supercooled viscous regime; how­ever, it is Jess accurate at low temperatures. The analysis suggests that non-Gaussian fluctuations are related to crystalline configurations. Implications for theories of the glass transition are discussed.
OriginalsprogEngelsk
Artikelnummer094505
TidsskriftJournal of Chemical Physics
Vol/bind150
Udgave nummer9
Antal sider11
ISSN0021-9606
DOI
StatusUdgivet - 4 mar. 2019

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