Study of local density enhancement in near-critical solutions of attractive solutes using hydrostatic hypernetted chain theory

The properties of infinitely dilute solutes in near-critical solvents often show a strong change in curvature when plotted against the bulk fluid density, in some cases even a plateau region is observed. In this article, it is shown that this phenomenon, due to a local solvent density enhancement, c...

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Autor principal: Fernández-Prini, R.
Formato: JOUR
Materias:
Bulk fluid densities
Near-critical solutions
Density of liquids
Molecules
Solvents
Spectroscopic analysis
Solutions
Acceso en línea:http://hdl.handle.net/20.500.12110/paper_10895647_v106_n12_p3217_FernandezPrini
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Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
id todo:paper_10895647_v106_n12_p3217_FernandezPrini
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spelling todo:paper_10895647_v106_n12_p3217_FernandezPrini2023-10-03T16:04:54Z Study of local density enhancement in near-critical solutions of attractive solutes using hydrostatic hypernetted chain theory Fernández-Prini, R. Bulk fluid densities Near-critical solutions Density of liquids Molecules Solvents Spectroscopic analysis Solutions The properties of infinitely dilute solutes in near-critical solvents often show a strong change in curvature when plotted against the bulk fluid density, in some cases even a plateau region is observed. In this article, it is shown that this phenomenon, due to a local solvent density enhancement, can be construed as a consequence of the linear response of fluids having large compressibilities when the solutes interact strongly with the solvent molecules. The hydrostatic hypernetted chain (HHNC) solution of the Ornstein-Zernike (OZ) equation for inhomogeneous fluids was used to calculate the solvent-solute radial distribution function and the number of solvent molecules that surround the solute particle for different solute-solvent interaction energies and reduced temperatures. The use of HHNC eliminates physically unsound features of the calculations, which employ theories for homogeneous fluids, and it also limits the extent and range of the local density enhancement. It is shown that the performance of the relatively simple HHNC theory is as satisfactory as that of more sophisticated theories and that it is able to describe adequately experimental spectroscopic and kinetic results confirming that the phenomenon involves the coupling of intermolecular interactions with the high susceptibility of the near-critical fluids. It is noted, however, that the magnitude of the solute-solvent interactions required to fit the experimental results are larger than expected from known values of the solutes' intermolecular energy (∈2/k). Fil:Fernández-Prini, R. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. JOUR info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_10895647_v106_n12_p3217_FernandezPrini
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-134
collection Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic Bulk fluid densities
Near-critical solutions
Density of liquids
Molecules
Solvents
Spectroscopic analysis
Solutions
spellingShingle Bulk fluid densities
Near-critical solutions
Density of liquids
Molecules
Solvents
Spectroscopic analysis
Solutions
Fernández-Prini, R.
Study of local density enhancement in near-critical solutions of attractive solutes using hydrostatic hypernetted chain theory
topic_facet Bulk fluid densities
Near-critical solutions
Density of liquids
Molecules
Solvents
Spectroscopic analysis
Solutions
description The properties of infinitely dilute solutes in near-critical solvents often show a strong change in curvature when plotted against the bulk fluid density, in some cases even a plateau region is observed. In this article, it is shown that this phenomenon, due to a local solvent density enhancement, can be construed as a consequence of the linear response of fluids having large compressibilities when the solutes interact strongly with the solvent molecules. The hydrostatic hypernetted chain (HHNC) solution of the Ornstein-Zernike (OZ) equation for inhomogeneous fluids was used to calculate the solvent-solute radial distribution function and the number of solvent molecules that surround the solute particle for different solute-solvent interaction energies and reduced temperatures. The use of HHNC eliminates physically unsound features of the calculations, which employ theories for homogeneous fluids, and it also limits the extent and range of the local density enhancement. It is shown that the performance of the relatively simple HHNC theory is as satisfactory as that of more sophisticated theories and that it is able to describe adequately experimental spectroscopic and kinetic results confirming that the phenomenon involves the coupling of intermolecular interactions with the high susceptibility of the near-critical fluids. It is noted, however, that the magnitude of the solute-solvent interactions required to fit the experimental results are larger than expected from known values of the solutes' intermolecular energy (∈2/k).
format JOUR
author Fernández-Prini, R.
author_facet Fernández-Prini, R.
author_sort Fernández-Prini, R.
title Study of local density enhancement in near-critical solutions of attractive solutes using hydrostatic hypernetted chain theory
title_short Study of local density enhancement in near-critical solutions of attractive solutes using hydrostatic hypernetted chain theory
title_full Study of local density enhancement in near-critical solutions of attractive solutes using hydrostatic hypernetted chain theory
title_fullStr Study of local density enhancement in near-critical solutions of attractive solutes using hydrostatic hypernetted chain theory
title_full_unstemmed Study of local density enhancement in near-critical solutions of attractive solutes using hydrostatic hypernetted chain theory
title_sort study of local density enhancement in near-critical solutions of attractive solutes using hydrostatic hypernetted chain theory
url http://hdl.handle.net/20.500.12110/paper_10895647_v106_n12_p3217_FernandezPrini
work_keys_str_mv AT fernandezprinir studyoflocaldensityenhancementinnearcriticalsolutionsofattractivesolutesusinghydrostatichypernettedchaintheory
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