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Mandal SS, Singh SK, Khan S. Role of site-site interaction on the phase equilibria of multiple-site associating fluids in a functionalized slit pore. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2023; 35:475402. [PMID: 37549673 DOI: 10.1088/1361-648x/acede1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/12/2023] [Accepted: 08/07/2023] [Indexed: 08/09/2023]
Abstract
Vapor-liquid phase equilibria for multiple sites associating fluids with different associating strengths are investigated in a slit pore using grand-canonical transition matrix Monte Carlo method. The increase of critical temperature from two-site to four-site associating fluids at constant site strength is quite significant as compared to that of the one-site to two-site associating fluids, which is more pronounced at higher associating strength (ϵ* = 6). Monomer fraction and cluster size distribution are used to investigate the association of fluid particles in coexistence phases. The monomer fraction for both phases decreases with increased associating sites on the fluid particles due to more site-site interaction with neighboring fluid particles and forming a larger cluster. Therefore, the number of associating sites and their distribution play a vital role in the association of fluid particles. Moreover, the saturation chemical potential changes with the arrangement of the sites. For two-site associating fluids, we observe early vapor-liquid transition when the sites are oppositely placed, and when the sites are placed at 90°, the vapor-liquid transition is observed at the higher chemical potential. Moreover, four-site associating fluids with a square arrangement show early vapor-liquid phase transition, mainly because these arrangements of sites effectively interact with surface sites and the molecules in the next layer.
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Affiliation(s)
- Sashanka Sekhar Mandal
- Department of Chemical & Biochemical Engineering, Indian Institute of Technology Patna, Patna 801103, India
| | - Sudhir Kumar Singh
- Department of Chemical Engineering, Thapar Institute of Engineering and Technology, Patiala 147004, India
| | - Sandip Khan
- Department of Chemical & Biochemical Engineering, Indian Institute of Technology Patna, Patna 801103, India
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Naincy Attri, Sudhir K. Singh. Estimation of Pore Critical Temperature of Nanoconfined Alkanes Using Vapour-Liquid Interfacial Free Energy. RUSSIAN JOURNAL OF PHYSICAL CHEMISTRY B 2021. [DOI: 10.1134/s1990793121090037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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3
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Confined Quantum Hard Spheres. ENTROPY 2021; 23:e23060775. [PMID: 34207472 PMCID: PMC8234891 DOI: 10.3390/e23060775] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Revised: 06/08/2021] [Accepted: 06/10/2021] [Indexed: 11/17/2022]
Abstract
We present computer simulation and theoretical results for a system of N Quantum Hard Spheres (QHS) particles of diameter σ and mass m at temperature T, confined between parallel hard walls separated by a distance Hσ, within the range 1≤H≤∞. Semiclassical Monte Carlo computer simulations were performed adapted to a confined space, considering effects in terms of the density of particles ρ*=N/V, where V is the accessible volume, the inverse length H−1 and the de Broglie’s thermal wavelength λB=h/2πmkT, where k and h are the Boltzmann’s and Planck’s constants, respectively. For the case of extreme and maximum confinement, 0.5<H−1<1 and H−1=1, respectively, analytical results can be given based on an extension for quantum systems of the Helmholtz free energies for the corresponding classical systems.
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4
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Turci F, Wilding NB. Phase Separation and Multibody Effects in Three-Dimensional Active Brownian Particles. PHYSICAL REVIEW LETTERS 2021; 126:038002. [PMID: 33543975 DOI: 10.1103/physrevlett.126.038002] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Accepted: 12/14/2020] [Indexed: 06/12/2023]
Abstract
Simulation studies of the phase diagram of repulsive active Brownian particles in three dimensions reveal that the region of motility-induced phase separation between a high and low density phase is enclosed by a region of gas-crystal phase separation. Near-critical loci and structural crossovers can additionally be identified in analogy with simple fluids. Motivated by the striking similarity to the behavior of equilibrium fluids with short-ranged pairwise attractions, we show that a direct mapping to pair potentials in the dilute limit implies interactions that are insufficiently attractive to engender phase separation. Instead, this is driven by the emergence of multibody effects associated with particle caging that occurs at sufficiently high number density. We quantify these effects via information-theoretical measures of n-body effective interactions extracted from the configurational structure.
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Affiliation(s)
- Francesco Turci
- H. H. Wills Physics Laboratory, Tyndall Avenue, Bristol, BS8 1TL, United Kingdom
| | - Nigel B Wilding
- H. H. Wills Physics Laboratory, Tyndall Avenue, Bristol, BS8 1TL, United Kingdom
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Singh SK. Critical temperature estimation of bulk and confined atomic fluid using vapour−liquid interfacial free energy. MOLECULAR SIMULATION 2018. [DOI: 10.1080/08927022.2017.1355554] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Affiliation(s)
- Sudhir K. Singh
- Department of Chemical Engineering, Thapar University, Patiala, India
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6
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Helmi A, Esrafili MD. A hard sphere fluid with quantum correction in nanospherical pores: A DFT study. J Mol Liq 2017. [DOI: 10.1016/j.molliq.2017.04.134] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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7
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De Luca S, Kannam SK, Todd BD, Frascoli F, Hansen JS, Daivis PJ. Effects of Confinement on the Dielectric Response of Water Extends up to Mesoscale Dimensions. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2016; 32:4765-4773. [PMID: 27115841 DOI: 10.1021/acs.langmuir.6b00791] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The extent of confinement effects on water is not clear in the literature. While some properties are affected only within a few nanometers from the wall surface, others are affected over long length scales, but the range is not clear. In this work, we have examined the dielectric response of confined water under the influence of external electric fields along with the dipolar fluctuations at equilibrium. The confinement induces a strong anisotropic effect which is evident up to 100 nm channel width, and may extend to macroscopic dimensions. The root-mean-square fluctuations of the total orientational dipole moment in the direction perpendicular to the surfaces is 1 order of magnitude smaller than the value attained in the parallel direction and is independent of the channel width. Consequently, the isotropic condition is unlikely to be recovered until the channel width reaches macroscopic dimensions. Consistent with dipole moment fluctuations, the effect of confinement on the dielectric response also persists up to channel widths considerably beyond 100 nm. When an electric field is applied in the perpendicular direction, the orientational relaxation is 3 orders of magnitude faster than the dipolar relaxation in the parallel direction and independent of temperature.
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Affiliation(s)
- Sergio De Luca
- School of Chemical Engineering, Integrated Material Design Centre (IMDC), University of New South Wales , Sydney, NSW 2033, Australia
| | | | | | | | - J S Hansen
- DNRF Center "Glass and Time", IMFUFA, Department of Science and Environment, Roskilde University , DK-4000 Roskilde, Denmark
| | - Peter J Daivis
- School of Applied Sciences, RMIT University , Melbourne, Victoria 3001, Australia
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Furlan AP, Fiore CE, Barbosa MC. Influence of disordered porous media on the anomalous properties of a simple water model. Phys Rev E 2015; 92:032404. [PMID: 26465479 DOI: 10.1103/physreve.92.032404] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2015] [Indexed: 11/06/2022]
Abstract
The thermodynamic, dynamic, and structural behavior of a water-like system confined in a matrix is analyzed for increasing confining geometries. The liquid is modeled by a two-dimensional associating lattice gas model that exhibits density and diffusion anomalies, similar to the anomalies present in liquid water. The matrix is a triangular lattice in which fixed obstacles impose restrictions to the occupation of the particles. We show that obstacles shorten all lines, including the phase coexistence, the critical and the anomalous lines. The inclusion of a very dense matrix not only suppresses the anomalies but also the liquid-liquid critical point.
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Affiliation(s)
- A P Furlan
- Instituto de Física, Univeridade Federal do Rio Grande do Sul, Caixa Postal 15051, 91501-570, Porto Alegre, RS, Brazil
| | - Carlos E Fiore
- Instituto de Física, Universidade de São Paulo, Caixa Postal 19044, 81531 São Paulo, SP, Brazil
| | - M C Barbosa
- Instituto de Física, Univeridade Federal do Rio Grande do Sul, Caixa Postal 15051, 91501-570, Porto Alegre, RS, Brazil
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Leoni F, Franzese G. Structural behavior and dynamics of an anomalous fluid between attractive and repulsive walls: Templating, molding, and superdiffusion. J Chem Phys 2014; 141:174501. [DOI: 10.1063/1.4899256] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Affiliation(s)
- Fabio Leoni
- Departament de Fisica Fonamental, Universitat de Barcelona, Martí i Franquès 1, 08028 Barcelona, Spain
| | - Giancarlo Franzese
- Departament de Fisica Fonamental, Universitat de Barcelona, Martí i Franquès 1, 08028 Barcelona, Spain
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Trejos VM, Gil-Villegas A, Martinez A. Computer simulation of liquid-vapor coexistence of confined quantum fluids. J Chem Phys 2014; 139:184505. [PMID: 24320282 DOI: 10.1063/1.4829769] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
The liquid-vapor coexistence (LV) of bulk and confined quantum fluids has been studied by Monte Carlo computer simulation for particles interacting via a semiclassical effective pair potential Veff(r) = VLJ + VQ, where VLJ is the Lennard-Jones 12-6 potential (LJ) and VQ is the first-order Wigner-Kirkwood (WK-1) quantum potential, that depends on β = 1∕kT and de Boer's quantumness parameter Λ=h/σ√mε, where k and h are the Boltzmann's and Planck's constants, respectively, m is the particle's mass, T is the temperature of the system, and σ and ε are the LJ potential parameters. The non-conformal properties of the system of particles interacting via the effective pair potential Veff(r) are due to Λ, since the LV phase diagram is modified by varying Λ. We found that the WK-1 system gives an accurate description of the LV coexistence for bulk phases of several quantum fluids, obtained by the Gibbs Ensemble Monte Carlo method (GEMC). Confinement effects were introduced using the Canonical Ensemble (NVT) to simulate quantum fluids contained within parallel hard walls separated by a distance Lp, within the range 2σ ≤ Lp ≤ 6σ. The critical temperature of the system is reduced by decreasing Lp and increasing Λ, and the liquid-vapor transition is not longer observed for Lp∕σ < 2, in contrast to what has been observed for the classical system.
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Affiliation(s)
- Víctor M Trejos
- 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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11
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Bianco V, Franzese G. Critical behavior of a water monolayer under hydrophobic confinement. Sci Rep 2014; 4:4440. [PMID: 24699181 PMCID: PMC3975237 DOI: 10.1038/srep04440] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2013] [Accepted: 03/06/2014] [Indexed: 12/16/2022] Open
Abstract
The properties of water can have a strong dependence on the confinement. Here, we consider a water monolayer nanoconfined between hydrophobic parallel walls under conditions that prevent its crystallization. We investigate, by simulations of a many-body coarse-grained water model, how the properties of the liquid are affected by the confinement. We show, by studying the response functions and the correlation length and by performing finite-size scaling of the appropriate order parameter, that at low temperature the monolayer undergoes a liquid-liquid phase transition ending in a critical point in the universality class of the two-dimensional (2D) Ising model. Surprisingly, by reducing the linear size L of the walls, keeping the walls separation h constant, we find a 2D-3D crossover for the universality class of the liquid-liquid critical point for L=h ≃ 50, i.e. for a monolayer thickness that is small compared to its extension. This result is drastically different from what is reported for simple liquids, where the crossover occurs for L=h ≃ 5, and is consistent with experimental results and atomistic simulations. We shed light on these findings showing that they are a consequence of the strong cooperativity and the low coordination number of the hydrogen bond network that characterizes water.
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Affiliation(s)
- Valentino Bianco
- Departament de Física Fonamental, Universitat de Barcelona, Martí i Franquès 1, ES-08028 Barcelona, Spain
| | - Giancarlo Franzese
- Departament de Física Fonamental, Universitat de Barcelona, Martí i Franquès 1, ES-08028 Barcelona, Spain
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12
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Lang S, Franosch T, Schilling R. Structural quantities of quasi-two-dimensional fluids. J Chem Phys 2014; 140:104506. [DOI: 10.1063/1.4867284] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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13
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Miyahara MT, Numaguchi R, Hiratsuka T, Nakai K, Tanaka H. Fluids in nanospaces: molecular simulation studies to find out key mechanisms for engineering. ADSORPTION 2013. [DOI: 10.1007/s10450-013-9588-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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14
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Kesselring TA, Lascaris E, Franzese G, Buldyrev SV, Herrmann HJ, Stanley HE. Finite-size scaling investigation of the liquid-liquid critical point in ST2 water and its stability with respect to crystallization. J Chem Phys 2013; 138:244506. [DOI: 10.1063/1.4808355] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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15
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Singh SK, Singh JK. A comparative study of critical temperature estimation of atomic fluid and chain molecules using fourth-order Binder cumulant and simplified scaling laws. MOLECULAR SIMULATION 2013. [DOI: 10.1080/08927022.2012.708755] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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16
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Franosch T, Lang S, Schilling R. Fluids in extreme confinement. PHYSICAL REVIEW LETTERS 2012; 109:240601. [PMID: 23368297 DOI: 10.1103/physrevlett.109.240601] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2012] [Indexed: 06/01/2023]
Abstract
For extremely confined fluids with a two-dimensional density n in slit geometry of an accessible width L, we prove that in the limit L → 0, the lateral and transversal degrees of freedom decouple, and the latter become ideal-gas-like. For a small wall separation, the transverse degrees of freedom can be integrated out and renormalize the interaction potential. We identify nL(2) as the hidden smallness parameter of the confinement problem and evaluate the effective two-body potential analytically, which allows calculating the leading correction to the free energy exactly. Explicitly, we map a fluid of hard spheres in extreme confinement onto a 2D fluid of disks with an effective hard-core diameter and a soft boundary layer. Two-dimensional phase transitions are robust and the transition point experiences a shift O(nL(2)).
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Affiliation(s)
- Thomas Franosch
- Institut für Theoretische Physik, Friedrich-Alexander-Universität Erlangen-Nürnberg, Staudtstraße 7, 91058 Erlangen, Germany
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Das A, Chakrabarti J. Dimensional crossover in fluids under nanometer-scale confinement. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2012; 85:050601. [PMID: 23004694 DOI: 10.1103/physreve.85.050601] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/26/2011] [Revised: 03/27/2012] [Indexed: 06/01/2023]
Abstract
Several earlier studies have shown signatures of crossover in various static and dynamics properties of a confined fluid when the confining dimension decreases to about a nanometer. The density fluctuations govern the majority of such properties of a fluid. Here, we illustrate the crossover in density fluctuation in a confined fluid, to provide a generic understanding of confinement-induced crossover of fluid properties, using computer simulations. The crossover can be understood as a manifestation of changes in the long-wavelength behavior of fluctuation in density due to geometrical constraints. We further show that the confining potential significantly affects the crossover behavior.
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Affiliation(s)
- Amit Das
- Department of Chemical, Biological and Macromolecular Sciences, S. N. Bose National Centre for Basic Sciences, Block JD, Sector III, Salt Lake, Kolkata-700 098, India.
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Han S, Yu CC. Widom line and noise-power spectral analysis of a supercritical fluid. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2012; 85:051201. [PMID: 23004739 DOI: 10.1103/physreve.85.051201] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2011] [Indexed: 06/01/2023]
Abstract
We have performed extensive molecular dynamics simulations to study noise-power spectra of density and potential energy fluctuations of a Lennard-Jones model of a fluid in the supercritical region. Emanating from the liquid-vapor critical point, there is a locus of isobaric specific heat maxima, called the Widom line, which is often regarded as an extension of the liquid-vapor coexistence line. Our simulation results show that the noise-power spectrum of the density fluctuations on the Widom line of the liquid-vapor transition exhibits three distinct 1/f^{γ} behaviors with exponents γ=0, 1.2, and 2, depending on the frequency f. We find that the intermediate frequency region with an exponent γ∼ 1 appears as the temperature approaches the Widom temperature from above or below. On the other hand, we do not find three distinct regions of 1/f^{γ} in the power spectrum of the potential energy fluctuations on the Widom line. Furthermore, we find that the power spectra of both the density and potential energy fluctuations at low frequency have a maximum on the Widom line, suggesting that the noise power can provide an alternative signature of the Widom line.
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Affiliation(s)
- Sungho Han
- Department of Physics and Astronomy, University of California, Irvine, California 92697, USA
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Singh SK, Singh JK, Kwak SK, Deo G. Phase transition and crossover behavior of colloidal fluids under confinement. Chem Phys Lett 2010. [DOI: 10.1016/j.cplett.2010.06.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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