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ID 53634
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Author
Mochizuki, Kenji Kaken ID
Abstract
Nanoconfined liquid water can transform into low-dimensional ices whose crystalline structures are dissimilar to any bulk ices and whose melting point may significantly rise with reducing the pore size, as revealed by computer simulation and confirmed by experiment. One of the intriguing, and as yet unresolved, questions concerns the observation that the liquid water may transform into a low-dimensional ice either via a first-order phase change or without any discontinuity in thermodynamic and dynamic properties, which suggests the existence of solid−liquid critical points in this class of nanoconfined systems. Here we explore the phase behavior of a model of water in carbon nanotubes in the temperature−pressure−diameter space by molecular dynamics simulation and provide unambiguous evidence to support solid−liquid critical phenomena of nanoconfined water. Solid−liquid first-order phase boundaries are determined by tracing spontaneous phase separation at various temperatures. All of the boundaries eventually cease to exist at the critical points and there appear loci of response function maxima, or the Widom lines, extending to the supercritical region. The finite-size scaling analysis of the density distribution supports the presence of both first-order and continuous phase changes between solid and liquid. At around the Widom line, there are microscopic domains of two phases, and continuous solid−liquid phase changes occur in such a way that the domains of one phase grow and those of the other evanesce as the thermodynamic state departs from the Widom line.
Keywords
water
solid−liquid critical point
carbon nanotube
ice
Widom line
Note
The final publication is available at PNAS via http://www.pnas.org/content/112/27/8221
Published Date
2015-07-07
Publication Title
Proceedings of the National Academy of Sciences of the United States of America
Volume
volume112
Issue
issue27
Publisher
National Academy of Sciences.
Start Page
8221
End Page
8226
ISSN
0027-8424
NCID
AA10808769
Content Type
Journal Article
Official Url
http://www.pnas.org/
language
英語
Copyright Holders
Copyright© 2015 Kenji Mochizuki and Kenichiro Koga; licensee National Academy of Sciences.
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True
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