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Martínez-Borquez A, Trejos VM, Hernandez-Guzman AJ, Gil-Villegas A. Microcanonical-ensemble perturbation theory for thermodynamic and diffusion properties of square-well fluids. J Mol Liq 2022. [DOI: 10.1016/j.molliq.2022.120434] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
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2
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López-Picón J, Escamilla-Herrera L, Torres-Arenas J. The square-well fluid: A thermodynamic geometric view. J Mol Liq 2022. [DOI: 10.1016/j.molliq.2022.120607] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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3
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Gurin P, Varga S, Odriozola G. The role of the second virial coefficient in the vapor-liquid phase coexistence of anisotropic square-well particles. J Mol Liq 2022. [DOI: 10.1016/j.molliq.2022.119528] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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4
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Russo J, Leoni F, Martelli F, Sciortino F. The physics of empty liquids: from patchy particles to water. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2022; 85:016601. [PMID: 34905739 DOI: 10.1088/1361-6633/ac42d9] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Accepted: 12/14/2021] [Indexed: 06/14/2023]
Abstract
Empty liquids represent a wide class of materials whose constituents arrange in a random network through reversible bonds. Many key insights on the physical properties of empty liquids have originated almost independently from the study of colloidal patchy particles on one side, and a large body of theoretical and experimental research on water on the other side. Patchy particles represent a family of coarse-grained potentials that allows for a precise control of both the geometric and the energetic aspects of bonding, while water has arguably the most complex phase diagram of any pure substance, and a puzzling amorphous phase behavior. It was only recently that the exchange of ideas from both fields has made it possible to solve long-standing problems and shed new light on the behavior of empty liquids. Here we highlight the connections between patchy particles and water, focusing on the modelling principles that make an empty liquid behave like water, including the factors that control the appearance of thermodynamic and dynamic anomalies, the possibility of liquid-liquid phase transitions, and the crystallization of open crystalline structures.
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Affiliation(s)
- John Russo
- Department of Physics, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185 Rome, Italy
| | - Fabio Leoni
- Department of Physics, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185 Rome, Italy
| | - Fausto Martelli
- IBM Research Europe, Hartree Centre, Daresbury WA4 4AD, United Kingdom
| | - Francesco Sciortino
- Department of Physics, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185 Rome, Italy
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5
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Gómez de Santiago M, Gurin P, Varga S, Odriozola G. Extended law of corresponding states: square-well oblates. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2021; 34:104002. [PMID: 34874295 DOI: 10.1088/1361-648x/ac3fd8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2021] [Accepted: 12/03/2021] [Indexed: 06/13/2023]
Abstract
The vapour-liquid coexistence collapse in the reduced temperature,Tr=T/Tc, reduced density,ρr=ρ/ρc, plane is known as a principle of corresponding states, and Noro and Frenkel have extended it for pair potentials of variable range. Here, we provide a theoretical basis supporting this extension, and show that it can also be applied to short-range pair potentials where both repulsive and attractive parts can be anisotropic. We observe that the binodals of oblate hard ellipsoids for a given aspect ratio (κ= 1/3) with varying short-range square-well interactions collapse into a single master curve in theΔB2*-ρrplane, whereΔB2*=(B2(T)-B2(Tc))/v0,B2is the second virial coefficient, andv0is the volume of the hard body. This finding is confirmed by both REMC simulation and second virial perturbation theory for varying square-well shells, mimicking uniform, equator, and pole attractions. Our simulation results reveal that the extended law of corresponding states is not related to the local structure of the fluid.
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Affiliation(s)
- Miguel Gómez de Santiago
- Área de Física de Procesos Irreversibles, División de Ciencias Básicas e Ingeniería, Universidad Autónoma Metropolitana-Azcapotzalco, Av. San Pablo 180, 02200 Ciudad de México, Mexico
| | - Péter Gurin
- Physics Department, Center for Natural Sciences, Faculty of Engineering, University of Pannonia, PO Box 158, Veszprém H-8201, Hungary
| | - Szabolcs Varga
- Physics Department, Center for Natural Sciences, Faculty of Engineering, University of Pannonia, PO Box 158, Veszprém H-8201, Hungary
| | - Gerardo Odriozola
- Área de Física de Procesos Irreversibles, División de Ciencias Básicas e Ingeniería, Universidad Autónoma Metropolitana-Azcapotzalco, Av. San Pablo 180, 02200 Ciudad de México, Mexico
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6
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Perdomo-Hurtado L, Valadez-Pérez NE, Millan-Malo B, Castañeda-Priego R. Generalized equation of state for fluids: From molecular liquids to colloidal dispersions. J Chem Phys 2021; 154:084902. [PMID: 33639744 DOI: 10.1063/5.0037630] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
In this work, a new parameterization for the Statistical Association Fluid Theory for potentials of Variable Range (SAFT-VR) is coupled to the discrete potential theory to represent the thermodynamic properties of several fluids, ranging from molecular liquids to colloidal-like dispersions. In this way, this version of the SAFT-VR approach can be straightforwardly applied to any kind of either simple or complex fluid. In particular, two interaction potentials, namely, the Lennard-Jones and the hard-core attractive Yukawa potentials, are discretized to study the vapor-liquid equilibrium properties of both molecular and complex liquids, respectively. Our results are assessed with Monte Carlo computer simulations and available and accurate theoretical results based on the self-consistent Ornstein-Zernike approximation.
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Affiliation(s)
- Luis Perdomo-Hurtado
- Grupo de Investigación Diseño Mecánico y Desarrollo Industrial, Universidad Autónoma de Manizales, Antigua Estación del Ferrocarril, Manizales, Caldas, Colombia
| | - Néstor Enrique Valadez-Pérez
- Facultad de Ciencias en Física y Matemáticas, Universidad Autónoma de Chiapas, Tuxtla Gutiérrez, Chiapas, Mexico
| | - Beatriz Millan-Malo
- Centro de Física Aplicada y Tecnología Avanzada, Universidad Nacional Autónoma de México, A.P. 1-1010, Querétaro 76000, Mexico
| | - Ramón Castañeda-Priego
- Departamento de Ingeniería Física, División de Ciencias e Ingenierías, Campus León, Universidad de Guanajuato, Loma del Bosque 103, Lomas del Campestre, 37150 León, Guanajuato, Mexico
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7
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A Thermodynamic Approach for the Prediction of Oiling Out Boundaries from Solubility Data. Processes (Basel) 2019. [DOI: 10.3390/pr7090577] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Many pharmaceutical molecules, fine chemicals, and proteins exhibit liquid–liquid phase separation (LLPS, also known as oiling out) during solution crystallization. LLPS is of significant concern in crystallization process development, as oiling out can compromise the effectiveness of a crystallization and can lead to operational problems. A comprehensive methodology that allows a process scientist/engineer to characterize the various phase boundaries relevant to oiling out is currently lacking. In this work, we present a modeling framework useful in predicting the binodal, spinodal, and gelation boundaries starting from the solubility data of a solute that is prone to oiling out. We collate the necessary theoretical concepts from the literature and describe a unified approach to model the phase equilibria of solute–solvent systems from first principles. The modeling effort is validated using experimental data reported in the literature for various solute–solvent systems. The predictive methods presented in this work can be easily implemented and help a process engineer establish the design space for a crystallization process that is affected by liquid–liquid phase separation.
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Trejos VM, Santos A, Gámez F. Vapor-liquid equilibrium and equation of state of two-dimensional fluids from a discrete perturbation theory. J Chem Phys 2018; 148:194505. [PMID: 30307191 DOI: 10.1063/1.5029375] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
The interest in the description of the properties of fluids of restricted dimensionality is growing for theoretical and practical reasons. In this work, we have firstly developed an analytical expression for the Helmholtz free energy of the two-dimensional square-well fluid in the Barker-Henderson framework. This equation of state is based on an approximate analytical radial distribution function for d-dimensional hard-sphere fluids (1 ≤ d ≤ 3) and is validated against existing and new simulation results. The so-obtained equation of state is implemented in a discrete perturbation theory able to account for general potential shapes. The prototypical Lennard-Jones and Yukawa fluids are tested in its two-dimensional version against available and new simulation data with semiquantitative agreement.
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Affiliation(s)
- Víctor M Trejos
- Instituto de Química, Universidad Nacional Autónoma de México, Apdo. Postal 70213, Coyoacán, 04510 Ciudad de México, Mexico
| | - Andrés Santos
- Departamento de Física and Instituto de Computación Científica Avanzada (ICCAEx), Universidad de Extremadura, 060006 Badajoz, Spain
| | - Francisco Gámez
- Department of Physical, Chemical and Natural Systems, Universidad Pablo de Olavide, 41013 Seville, Spain
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Trejos VM, Martínez A, Valadez-Pérez NE. Statistical fluid theory for systems of variable range interacting via triangular-well pair potential. J Mol Liq 2018. [DOI: 10.1016/j.molliq.2018.05.116] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
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10
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Cripwell JT, Smith SAM, Schwarz CE, Burger AJ. SAFT-VR Mie: Application to Phase Equilibria of Alcohols in Mixtures with n-Alkanes and Water. Ind Eng Chem Res 2018. [DOI: 10.1021/acs.iecr.8b01042] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Jamie T. Cripwell
- Department of Process Engineering, Stellenbosch University, Private Bag X1, Matieland, 7602, South Africa
| | - Sonja A. M. Smith
- Department of Process Engineering, Stellenbosch University, Private Bag X1, Matieland, 7602, South Africa
| | - Cara E. Schwarz
- Department of Process Engineering, Stellenbosch University, Private Bag X1, Matieland, 7602, South Africa
| | - Andries J. Burger
- Department of Process Engineering, Stellenbosch University, Private Bag X1, Matieland, 7602, South Africa
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11
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Zerón IM, Vega C, Benavides AL. Continuous version of a square-well potential of variable range and its application in molecular dynamics simulations. Mol Phys 2018. [DOI: 10.1080/00268976.2018.1481232] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Affiliation(s)
- I. M. Zerón
- División de Ciencias e Ingenierías, Universidad de Guanajuato, Guanajuato, México
| | - C. Vega
- Depto. Química Física I, Fac. Ciencias Químicas, Universidad Complutense de Madrid, 28040, Madrid, Spain
| | - A. L. Benavides
- División de Ciencias e Ingenierías, Universidad de Guanajuato, Guanajuato, México
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12
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Sastre F, Moreno-Hilario E, Sotelo-Serna MG, Gil-Villegas A. Microcanonical-ensemble computer simulation of the high-temperature expansion coefficients of the Helmholtz free energy of a square-well fluid. Mol Phys 2017. [DOI: 10.1080/00268976.2017.1392051] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- Francisco Sastre
- Departamento de Ingeniería Física, División de Ciencias e Ingenierías, Campus León de la Universidad de Guanajuato, AP E-143, 37150, Leon, Mexico
| | - Elizabeth Moreno-Hilario
- División de Ciencias e Ingenierías, Campus León de la Universidad de Guanajuato, AP E-143, 37150, Leon, Mexico
| | | | - Alejandro Gil-Villegas
- Departamento de Ingeniería Física, División de Ciencias e Ingenierías, Campus León de la Universidad de Guanajuato, AP E-143, 37150, Leon, Mexico
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13
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Padilla LA, Benavides AL. The constant force continuous molecular dynamics for potentials with multiple discontinuities. J Chem Phys 2017; 147:034502. [PMID: 28734278 DOI: 10.1063/1.4993436] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
In this work, we present an extension of the constant force approach [P. Orea and G. Odriozola, J. Chem. Phys. 138, 214105 (2013)] to the case of potentials with multiple discontinuities. To illustrate the method, we selected the square well potential of range λ=1.5 that exhibits two discontinuities. Square well single phase properties, vapor-liquid phase diagram, and surface tension were calculated and compared with available simulation data. Besides, we analyzed the internal energies of a square well plus a square shoulder potential having three discontinuities. For both potentials, a good agreement has been found when compared with results of other simulation techniques (discontinuous molecular dynamics and Monte Carlo methods). This extension can be easily implemented to more general and efficient continuous molecular dynamics packages (HOOMD, GROMACS, NAMD, etc.).
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Affiliation(s)
- L A Padilla
- División de Ciencias e Ingenierías, Universidad de Guanajuato, Loma del Bosque 103, Colonia Lomas del Campestre, CP 37150 León, Guanajuato, Mexico
| | - A L Benavides
- División de Ciencias e Ingenierías, Universidad de Guanajuato, Loma del Bosque 103, Colonia Lomas del Campestre, CP 37150 León, Guanajuato, Mexico
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14
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15
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16
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Orea P, Varga S, Odriozola G. A heuristic rule for classification of classical fluids: Master curves for Mie, Yukawa and square-well potentials. Chem Phys Lett 2015. [DOI: 10.1016/j.cplett.2015.04.025] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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17
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Guérin H. Unified SAFT-VR theory for simple and chain fluids formed of square-well, triangular-well, Sutherland and Mie segments. J Mol Liq 2015. [DOI: 10.1016/j.molliq.2015.01.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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18
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del Río F, Díaz-Herrera E, Guzmán O, Moreno-Razo JA, Ramos JE. Analytical equation of state with three-body forces: Application to noble gases. J Chem Phys 2013; 139:184503. [DOI: 10.1063/1.4829055] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
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19
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Lafitte T, Apostolakou A, Avendaño C, Galindo A, Adjiman CS, Müller EA, Jackson G. Accurate statistical associating fluid theory for chain molecules formed from Mie segments. J Chem Phys 2013; 139:154504. [DOI: 10.1063/1.4819786] [Citation(s) in RCA: 304] [Impact Index Per Article: 27.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
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20
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Molecular Dynamics at Constant Pressure: Allowing the System to Control Volume Fluctuations via a “Shell” Particle. ENTROPY 2013. [DOI: 10.3390/e15093941] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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21
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Zhao W, Wu L, Wang L, Li L, Cai J. Critical asymmetry in renormalization group theory for fluids. J Chem Phys 2013; 138:234502. [PMID: 23802966 DOI: 10.1063/1.4810809] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The renormalization-group (RG) approaches for fluids are employed to investigate critical asymmetry of vapour-liquid equilibrium (VLE) of fluids. Three different approaches based on RG theory for fluids are reviewed and compared. RG approaches are applied to various fluid systems: hard-core square-well fluids of variable ranges, hard-core Yukawa fluids, and square-well dimer fluids and modelling VLE of n-alkane molecules. Phase diagrams of simple model fluids and alkanes described by RG approaches are analyzed to assess the capability of describing the VLE critical asymmetry which is suggested in complete scaling theory. Results of thermodynamic properties obtained by RG theory for fluids agree with the simulation and experimental data. Coexistence diameters, which are smaller than the critical densities, are found in the RG descriptions of critical asymmetries of several fluids. Our calculation and analysis show that the approach coupling local free energy with White's RG iteration which aims to incorporate density fluctuations into free energy is not adequate for VLE critical asymmetry due to the inadequate order parameter and the local free energy functional used in the partition function.
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Affiliation(s)
- Wei Zhao
- Department of Chemistry, East China University of Science and Technology, Shanghai 200237, China
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22
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Ramana ASV, Menon SVG. Coupling-parameter expansion in thermodynamic perturbation theory. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2013; 87:022101. [PMID: 23496454 DOI: 10.1103/physreve.87.022101] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2012] [Revised: 12/15/2012] [Indexed: 06/01/2023]
Abstract
An approach to the coupling-parameter expansion in the liquid state theory of simple fluids is presented by combining the ideas of thermodynamic perturbation theory and integral equation theories. This hybrid scheme avoids the problems of the latter in the two phase region. A method to compute the perturbation series to any arbitrary order is developed and applied to square well fluids. Apart from the Helmholtz free energy, the method also gives the radial distribution function and the direct correlation function of the perturbed system. The theory is applied for square well fluids of variable ranges and compared with simulation data. While the convergence of perturbation series and the overall performance of the theory is good, improvements are needed for potentials with shorter ranges. Possible directions for further developments in the coupling-parameter expansion are indicated.
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Affiliation(s)
- A Sai Venkata Ramana
- Theoretical Physics Division, Bhabha Atomic Research Centre, Mumbai 400 085, India
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23
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Benavides AL, Delgado FJG, Gámez F, Lago S, Garzón B. Statistical thermodynamics of fluids with both dipole and quadrupole moments. J Chem Phys 2011; 134:234507. [PMID: 21702567 DOI: 10.1063/1.3599465] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
New Gibbs ensemble simulation data for a polar fluid modeled by a square-well potential plus dipole-dipole, dipole-quadrupole, and quadrupole-quadrupole interactions are presented. This simulation data is used in order to assess the applicability of the multipolar square-well perturbation theory [A. L. Benavides, Y. Guevara, and F. del Río, Physica A 202, 420 (1994)] to systems where more than one term in the multipole expansion is relevant. It is found that this theory is able to reproduce qualitatively well the vapor-liquid phase diagram for different multipolar moment strengths, corresponding to typical values of real molecules, except in the critical region. Hence, this theory is used to model the behavior of substances with multiple chemical bonds such as carbon monoxide and nitrous oxide and we found that with a suitable choice of the values of the intermolecular parameters, the vapor-liquid equilibrium of these species is adequately estimated.
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Affiliation(s)
- Ana L Benavides
- Departamento Ingeniería Física, División de Ciencias e Ingenierías, Campus León, Universidad de Guanajuato, Apdo. E-413, León, Guanajuato 37150, México.
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Jin Z, Tang Y, Wu J. A perturbative density functional theory for square-well fluids. J Chem Phys 2011; 134:174702. [DOI: 10.1063/1.3585677] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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25
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Forte E, Llovell F, Vega LF, Trusler JPM, Galindo A. Application of a renormalization-group treatment to the statistical associating fluid theory for potentials of variable range (SAFT-VR). J Chem Phys 2011; 134:154102. [DOI: 10.1063/1.3570614] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
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Guérin H. A new simple analytic equation of state for square-well chain fluids with variable width, 1.1<λ<2, based on perturbation theory and an analytic representation of the hard-sphere radial distribution function gHS(r). J Mol Liq 2010. [DOI: 10.1016/j.molliq.2010.07.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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28
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Herring AR, Henderson JR. Simulation study of the disjoining pressure profile through a three-phase contact line. J Chem Phys 2010; 132:084702. [DOI: 10.1063/1.3327840] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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29
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Apfelbaum EM, Vorob'ev VS. The confirmation of the critical point-Zeno-line similarity set from the numerical modeling data for different interatomic potentials. J Chem Phys 2009; 130:214111. [DOI: 10.1063/1.3151982] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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30
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Espíndola-Heredia R, del Río F, Malijevsky A. Optimized equation of the state of the square-well fluid of variable range based on a fourth-order free-energy expansion. J Chem Phys 2009; 130:024509. [DOI: 10.1063/1.3054361] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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31
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El Mendoub E, Wax JF, Charpentier I, Jakse N. Integral equation study of the square-well fluid for varying attraction range. Mol Phys 2008. [DOI: 10.1080/00268970802603499] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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32
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Uline MJ, Corti DS. Molecular dynamics in the isothermal-isobaric ensemble: the requirement of a "shell" molecule. III. Discontinuous potentials. J Chem Phys 2008; 129:014107. [PMID: 18624470 DOI: 10.1063/1.2949799] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Based on the approach of Gruhn and Monson [Phys. Rev. E 63, 061106 (2001)], we present a new method for deriving the collisions dynamics for particles that interact via discontinuous potentials. By invoking the conservation of the extended Hamiltonian, we generate molecular dynamics (MD) algorithms for simulating the hard-sphere and square-well fluids within the isothermal-isobaric (NpT) ensemble. Consistent with the recent rigorous reformulation of the NpT ensemble partition function, the equations of motion impose a constant external pressure via the introduction of a shell particle of known mass [M. J. Uline and D. S. Corti, J. Chem. Phys. 123, 164101 (2005); 123, 164102 (2005)], which serves to define uniquely the volume of the system. The particles are also connected to a temperature reservoir through the use of a chain of Nose-Hoover thermostats, the properties of which are not affected by a hard-sphere or square-well collision. By using the Liouville operator formalism and the Trotter expansion theorem to integrate the equations of motion, the update of the thermostat variables can be decoupled from the update of the positions of the particles and the momentum changes upon a collision. Hence, once the appropriate collision dynamics for the isobaric-isenthalpic (NpH) equations of motion is known, the adaptation of the algorithm to the NpT ensemble is straightforward. Results of MD simulations for the pure component square-well fluid are presented and serve to validate our algorithm. Finally, since the mass of the shell particle is known, the system itself, and not a piston of arbitrary mass, controls the time scales for internal pressure and volume fluctuations. We therefore consider the influence of the shell particle algorithm on the dynamics of the square-well fluid.
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Affiliation(s)
- Mark J Uline
- School of Chemical Engineering, Purdue University, West Lafayette, Indiana 47907-2100, USA
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33
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Alavi F, Feyzi F. An equation of state contribution for dipolar and quadrupolar square-well fluids. Mol Phys 2008. [DOI: 10.1080/00268970701871015] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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35
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Hu J, Duan Z, Shi X, Zhu J. A general local composition and coordination number model for square-well fluids with variable well width and diameter ratio. Mol Phys 2007. [DOI: 10.1080/00268970701262900] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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López-Rendón R, Reyes Y, Orea P. Thermodynamic properties of short-range square well fluid. J Chem Phys 2006; 125:084508. [PMID: 16965030 DOI: 10.1063/1.2338307] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The interfacial properties of short-range square well fluid with lambda=1.15, 1.25, and 1.375 were determined by using single canonical Monte Carlo simulations. Simulations were carried out in the vapor-liquid region. The coexistence curves of these models were calculated and compared to those previously reported in the literature and good agreement was found among them. We found that the surface tension curves for any potential model of short range form a single master curve when we plot gamma* vs TT(c). It is demonstrated that the critical reduced second virial coefficient B(2)* as a function of interaction range or T(c)* is not constant.
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Affiliation(s)
- R López-Rendón
- Departamento de Química UAM-Iztapalapa, Avenida San Rafael Atlixco 186, 09340 México D.F., México
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Tan SP, Ji X, Adidharma H, Radosz M. Statistical Associating Fluid Theory Coupled with Restrictive Primitive Model Extended to Bivalent Ions. SAFT2: 1. Single Salt + Water Solutions. J Phys Chem B 2006; 110:16694-9. [PMID: 16913808 DOI: 10.1021/jp0625107] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Statistical associating fluid theory coupled with the restricted primitive model is extended to multivalent ions by relaxing the range of the square-well width parameter, which leads to a new dispersion term approximation and calls for a new set of salt and ion parameters. This new approximation, referred to as SAFT2, requires a single set of parameters derived from the salt (mean ionic) activity coefficients and liquid densities of single-salt solutions for five cations (Li(+), Na(+), K(+), Ca(2+), Mg(2+)), six anions (Cl(-), Br(-), I(-), NO(3)(-), SO(4)(-2), HCO(3)(-)), and 24 salts. These parameters, in turn, are shown to predict the osmotic coefficients for single salt + water solutions.
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Affiliation(s)
- Sugata P Tan
- Soft Materials Laboratory, Department of Chemical and Petroleum Engineering, University of Wyoming, Laramie, Wyoming 82071-3295, USA
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Avendaño C, Gil-Villegas A. Monte Carlo simulations of primitive models for ionic systems using the Wolf method. Mol Phys 2006. [DOI: 10.1080/00268970600551155] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Paricaud P. A general perturbation approach for equation of state development: Applications to simple fluids, ab initio potentials, and fullerenes. J Chem Phys 2006; 124:154505. [PMID: 16674240 DOI: 10.1063/1.2181979] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
A new perturbation scheme based on the Barker-Henderson perturbation theory [J. Chem. Phys. 47, 4714 (1967)] is proposed to predict the thermodynamic properties of spherical molecules. Accurate predictions of second virial coefficients and vapor-liquid coexistence properties are obtained for a large variety of potential functions (square well, Yukawa, Sutherland, Lennard-Jones, Buckingham, Girifalco). New Gibbs ensemble Monte Carlo simulations of the generalized exp-m Buckingham potential are reported. An extension of the perturbation approach to mixtures is proposed, and excellent predictions of vapor-liquid equilibria are obtained for Lennard-Jones mixtures. The perturbation scheme can be applied to complex potential functions fitted to ab initio data to predict the properties of real molecules such as neon. The new approach can also be used as an auxiliary tool in molecular simulation studies, to efficiently optimize an intermolecular potential on macroscopic properties or match force fields based on different potential functions.
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Affiliation(s)
- Patrice Paricaud
- Laboratoire Chimie et Procédé, UCP-ENSTA, 32 Boulevard Victor, 75739 Paris, France.
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Schöll-Paschinger E, Benavides AL, Castañeda-Priego R. Vapor-liquid equilibrium and critical behavior of the square-well fluid of variable range: A theoretical study. J Chem Phys 2005; 123:234513. [PMID: 16392937 DOI: 10.1063/1.2137713] [Citation(s) in RCA: 85] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The vapor-liquid phase behavior and the critical behavior of the square-well (SW) fluid are investigated as a function of the interaction range, lambdain [1.25, 3], by means of the self-consistent Ornstein-Zernike approximation (SCOZA) and analytical equations of state based on a perturbation theory [A. L. Benavides and F. del Rio, Mol. Phys. 68, 983 (1989); A. Gil-Villegas, F. del Rio, and A. L. Benavides, Fluid Phase Equilib. 119, 97 (1996)]. For this purpose the SCOZA, which has been restricted up to now to a few model systems, has been generalized to hard-core systems with arbitrary interaction potentials requiring a fully numerical solution of an integro-partial differential equation. Both approaches, in general, describe well the liquid-vapor phase diagram of the square-well fluid when compared with simulation data. SCOZA yields very precise predictions for the coexistence curves in the case of long ranged SW interaction (lambda>1.5), and the perturbation theory is able to predict the binodal curves and the saturated pressures, for all interaction ranges considered if one stays away from the critical region. In all cases, the SCOZA gives very good predictions for the critical temperatures and the critical pressures, while the perturbation theory approach tends to slightly overestimate these quantities. Furthermore, we propose analytical expressions for the critical temperatures and pressures as a function of the square-well range.
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Sun L, Zhao H, Kiselev SB, McCabe C. Predicting Mixture Phase Equilibria and Critical Behavior Using the SAFT-VRX Approach. J Phys Chem B 2005; 109:9047-58. [PMID: 16852077 DOI: 10.1021/jp044413o] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The SAFT-VRX equation of state combines the SAFT-VR equation with a crossover function that smoothly transforms the classical equation into a nonanalytical form close to the critical point. By a combinination of the accuracy of the SAFT-VR approach away from the critical region with the asymptotic scaling behavior seen at the critical point of real fluids, the SAFT-VRX equation can accurately describe the global fluid phase diagram. In previous work, we demonstrated that the SAFT-VRX equation very accurately describes the pvT and phase behavior of both nonassociating and associating pure fluids, with a minimum of fitting to experimental data. Here, we present a generalized SAFT-VRX equation of state for binary mixtures that is found to accurately predict the vapor-liquid equilibrium and pvT behavior of the systems studied. In particular, we examine binary mixtures of n-alkanes and carbon dioxide + n-alkanes. The SAFT-VRX equation accurately describes not only the gas-liquid critical locus for these systems but also the vapor-liquid equilibrium phase diagrams and thermal properties in single-phase regions.
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Affiliation(s)
- Lixin Sun
- Department of Chemical Engineering, Vanderbilt University, Nashville, Tennessee 37235-1604, USA
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