Statistics of small length scale density fluctuations in supercooled viscous liquids

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Resumé

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/bind2019
Udgave nummer150
Antal sider11
ISSN0021-9606
DOI
StatusUdgivet - 4 mar. 2019

Citer dette

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title = "Statistics of small length scale density fluctuations in supercooled viscous liquids",
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 Wahnstr{\"o}m binary mixture, the Lewis-Wahnstr{\"o}m 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 less 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.",
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Statistics of small length scale density fluctuations in supercooled viscous liquids. / Pedersen, Ulf Rørbæk.

I: Journal of Chemical Physics, Bind 2019, Nr. 150, 094505, 04.03.2019.

Publikation: Bidrag til tidsskriftTidsskriftartikelForskningpeer review

TY - JOUR

T1 - Statistics of small length scale density fluctuations in supercooled viscous liquids

AU - Pedersen, Ulf Rørbæk

PY - 2019/3/4

Y1 - 2019/3/4

N2 - 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 Wahnström binary mixture, the Lewis-Wahnström 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 less 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.

AB - 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 Wahnström binary mixture, the Lewis-Wahnström 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 less 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.

UR - http://glass.ruc.dk/pdf/articles/2019_JChemPhys_150_094505.pdf

U2 - 10.1063/1.5080277

DO - 10.1063/1.5080277

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JO - Journal of Chemical Physics

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SN - 0021-9606

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