Theoretical characterization of the "ridge" in the supercritical region in the fluid phase diagram of water

Masaru Matsugami, Norio Yoshida, Fumio Hirata

Research output: Contribution to journalArticle

7 Citations (Scopus)

Abstract

The density fluctuation of water in the supercritical region was investigated theoretically using the reference interaction site model theory combined with the Kovalenko-Hirata closure relation, the so-called RISM-KH theory. The density fluctuation was evaluated by the numerical differentiation of density with respect to pressure at constant temperature. The density fluctuations plotted against density show finite maxima along a line slightly off from the critical isochore, in accordance with experimental results. The microscopic structures of water on both regions that were separated by the line were investigated by analyzing the site-site radial distribution functions. The analysis clearly indicates that the structure is determined by the two effects featuring liquid states: the packing or volume exclusion effect and the screening of the Coulomb interaction or the hydrogen bond, both becoming more important at higher densities. An interplay of the two effects creates maxima of the density fluctuation in the supercritical region of water.

Original languageEnglish
Article number104511
JournalJournal of Chemical Physics
Volume140
Issue number10
DOIs
Publication statusPublished - Mar 14 2014

Fingerprint

Phase diagrams
ridges
phase diagrams
Fluids
Water
fluids
Isochores
water
Coulomb interactions
Distribution functions
Hydrogen bonds
Screening
numerical differentiation
Liquids
exclusion
radial distribution
closures
screening
distribution functions
Temperature

All Science Journal Classification (ASJC) codes

  • Physics and Astronomy(all)
  • Physical and Theoretical Chemistry

Cite this

Theoretical characterization of the "ridge" in the supercritical region in the fluid phase diagram of water. / Matsugami, Masaru; Yoshida, Norio; Hirata, Fumio.

In: Journal of Chemical Physics, Vol. 140, No. 10, 104511, 14.03.2014.

Research output: Contribution to journalArticle

@article{3010f6913cf94cfb9ef18b3d0b54248b,
title = "Theoretical characterization of the {"}ridge{"} in the supercritical region in the fluid phase diagram of water",
abstract = "The density fluctuation of water in the supercritical region was investigated theoretically using the reference interaction site model theory combined with the Kovalenko-Hirata closure relation, the so-called RISM-KH theory. The density fluctuation was evaluated by the numerical differentiation of density with respect to pressure at constant temperature. The density fluctuations plotted against density show finite maxima along a line slightly off from the critical isochore, in accordance with experimental results. The microscopic structures of water on both regions that were separated by the line were investigated by analyzing the site-site radial distribution functions. The analysis clearly indicates that the structure is determined by the two effects featuring liquid states: the packing or volume exclusion effect and the screening of the Coulomb interaction or the hydrogen bond, both becoming more important at higher densities. An interplay of the two effects creates maxima of the density fluctuation in the supercritical region of water.",
author = "Masaru Matsugami and Norio Yoshida and Fumio Hirata",
year = "2014",
month = "3",
day = "14",
doi = "10.1063/1.4867974",
language = "English",
volume = "140",
journal = "Journal of Chemical Physics",
issn = "0021-9606",
publisher = "American Institute of Physics Publising LLC",
number = "10",

}

TY - JOUR

T1 - Theoretical characterization of the "ridge" in the supercritical region in the fluid phase diagram of water

AU - Matsugami, Masaru

AU - Yoshida, Norio

AU - Hirata, Fumio

PY - 2014/3/14

Y1 - 2014/3/14

N2 - The density fluctuation of water in the supercritical region was investigated theoretically using the reference interaction site model theory combined with the Kovalenko-Hirata closure relation, the so-called RISM-KH theory. The density fluctuation was evaluated by the numerical differentiation of density with respect to pressure at constant temperature. The density fluctuations plotted against density show finite maxima along a line slightly off from the critical isochore, in accordance with experimental results. The microscopic structures of water on both regions that were separated by the line were investigated by analyzing the site-site radial distribution functions. The analysis clearly indicates that the structure is determined by the two effects featuring liquid states: the packing or volume exclusion effect and the screening of the Coulomb interaction or the hydrogen bond, both becoming more important at higher densities. An interplay of the two effects creates maxima of the density fluctuation in the supercritical region of water.

AB - The density fluctuation of water in the supercritical region was investigated theoretically using the reference interaction site model theory combined with the Kovalenko-Hirata closure relation, the so-called RISM-KH theory. The density fluctuation was evaluated by the numerical differentiation of density with respect to pressure at constant temperature. The density fluctuations plotted against density show finite maxima along a line slightly off from the critical isochore, in accordance with experimental results. The microscopic structures of water on both regions that were separated by the line were investigated by analyzing the site-site radial distribution functions. The analysis clearly indicates that the structure is determined by the two effects featuring liquid states: the packing or volume exclusion effect and the screening of the Coulomb interaction or the hydrogen bond, both becoming more important at higher densities. An interplay of the two effects creates maxima of the density fluctuation in the supercritical region of water.

UR - http://www.scopus.com/inward/record.url?scp=84896351131&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84896351131&partnerID=8YFLogxK

U2 - 10.1063/1.4867974

DO - 10.1063/1.4867974

M3 - Article

AN - SCOPUS:84896351131

VL - 140

JO - Journal of Chemical Physics

JF - Journal of Chemical Physics

SN - 0021-9606

IS - 10

M1 - 104511

ER -