1
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Tanaka H, Matsumoto M, Yagasaki T, Takeuchi M, Mori Y, Kono T. Stability mechanism of crystalline CO2 and Xe. J Chem Phys 2024; 161:084501. [PMID: 39177089 DOI: 10.1063/5.0223879] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2024] [Accepted: 08/08/2024] [Indexed: 08/24/2024] Open
Abstract
We explore the phase behaviors of simple molecular crystals in order to investigate the molecular basis of the stability mechanism relative to their liquid counterparts. The free energies of the face centered cubic crystals of Xe and CO2 are calculated as a collection of oscillators, and those of the liquids are from an equation of state via molecular dynamics simulations. The vibrational free energy in the solid is separated into the harmonic and anharmonic terms. The harmonic free energies decrease harshly with the expansion of the volume manifested as the large positive Grüneisen parameters, but the anharmonic free energies are positive and increase with volume, both of which originate from the deviation of the potential surface from the parabolic curve. The anharmonic free energies, though less significant in magnitude and destabilize the solids thermodynamically, serve to enhance their mechanical stability. The solid-liquid phase boundaries cannot be settled correctly without the exquisite balance between the two opposing contributions. A sharp contrast regarding the solid free energy is found in low-pressure ice, where the harmonic free energy does not decrease monotonically with volume and its anharmonic free energy is negative.
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Affiliation(s)
- Hideki Tanaka
- Toyota Physical and Chemical Research Institute, Nagakute 480-1192, Japan
- Research Institute for Interdisciplinary Science, Okayama University, Okayama 700-8530, Japan
| | - Masakazu Matsumoto
- Research Institute for Interdisciplinary Science, Okayama University, Okayama 700-8530, Japan
| | - Takuma Yagasaki
- Division of Chemical Engineering, Graduate School of Engineering Science, Osaka University, Osaka 560-8531, Japan
| | - Munetaka Takeuchi
- Ochanomizu University, 2-1-1 Ohtsuka, Bunkyo-ku, Tokyo 112-8610, Japan
| | - Yoshihito Mori
- Ochanomizu University, 2-1-1 Ohtsuka, Bunkyo-ku, Tokyo 112-8610, Japan
| | - Takumi Kono
- Engineering Advancement Association of Japan, 1-11-9 Azabudai, Minato-ku, Tokyo 105-0001, Japan
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2
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Heyes DM, Dini D, Pieprzyk S, Brańka AC, Costigliola L. Models to predict configurational adiabats of Lennard-Jones fluids and their transport coefficients. J Chem Phys 2024; 161:084502. [PMID: 39193943 DOI: 10.1063/5.0225650] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2024] [Accepted: 08/08/2024] [Indexed: 08/29/2024] Open
Abstract
A comparison is made between three simple approximate formulas for the configurational adiabat (i.e., constant excess entropy, sex) lines in a Lennard-Jones (LJ) fluid, one of which is an analytic formula based on a harmonic approximation, which was derived by Heyes et al. [J. Chem. Phys. 159, 224504 (2023)] (analytic isomorph line, AIL). Another is where the density is normalized by the freezing density at that temperature (freezing isomorph line, FIL). It is found that the AIL formula and the average of the freezing density and the melting density ("FMIL") are configurational adiabats at all densities essentially down to the liquid-vapor binodal. The FIL approximation departs from a configurational adiabat in the vicinity of the liquid-vapor binodal close to the freezing line. The self-diffusion coefficient, D, shear viscosity, ηs, and thermal conductivity, λ, in macroscopic reduced units are essentially constant along the AIL and FMIL at all fluid densities and temperatures, but departures from this trend are found along the FIL at high liquid state densities near the liquid-vapor binodal. This supports growing evidence that for simple model systems with no or few internal degrees of freedom, isodynes are lines of constant excess entropy. It is shown that for the LJ fluid, ηs and D can be predicted accurately by an essentially analytic procedure from the high temperature limiting inverse power fluid values (apart from at very low densities), and this is demonstrated quite well also for the experimental argon viscosity.
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Affiliation(s)
- D M Heyes
- Department of Mechanical Engineering, Imperial College London, Exhibition Road, South Kensington, London SW7 2AZ, United Kingdom
| | - D Dini
- Department of Mechanical Engineering, Imperial College London, Exhibition Road, South Kensington, London SW7 2AZ, United Kingdom
| | - S Pieprzyk
- Institute of Molecular Physics, Polish Academy of Sciences, M. Smoluchowskiego 17, 60-179 Poznań, Poland
| | - A C Brańka
- Institute of Molecular Physics, Polish Academy of Sciences, M. Smoluchowskiego 17, 60-179 Poznań, Poland
| | - L Costigliola
- Department of Mechanical Engineering, Imperial College London, Exhibition Road, South Kensington, London SW7 2AZ, United Kingdom
- Glass and Time, IMFUFA, Department of Science and Environment, Roskilde University, P.O. Box 260, DK-4000 Roskilde, Denmark
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3
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Yang M, Pártay LB, Wexler RB. Surface phase diagrams from nested sampling. Phys Chem Chem Phys 2024; 26:13862-13874. [PMID: 38659377 DOI: 10.1039/d4cp00050a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/26/2024]
Abstract
Studies in atomic-scale modeling of surface phase equilibria often focus on temperatures near zero Kelvin due to the challenges in calculating the free energy of surfaces at finite temperatures. The Bayesian-inference-based nested sampling (NS) algorithm allows for modeling phase equilibria at arbitrary temperatures by directly and efficiently calculating the partition function, whose relationship with free energy is well known. This work extends NS to calculate adsorbate phase diagrams, incorporating all relevant configurational contributions to the free energy. We apply NS to the adsorption of Lennard-Jones (LJ) gas particles on low-index and vicinal LJ solid surfaces and construct the canonical partition function from these recorded energies to calculate ensemble averages of thermodynamic properties, such as the constant-volume heat capacity and order parameters that characterize the structure of adsorbate phases. Key results include determining the nature of phase transitions of adsorbed LJ particles on flat and stepped LJ surfaces, which typically feature an enthalpy-driven condensation at higher temperatures and an entropy-driven reordering process at lower temperatures, and the effect of surface geometry on the presence of triple points in the phase diagrams. Overall, we demonstrate the ability and potential of NS for surface modeling.
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Affiliation(s)
- Mingrui Yang
- Department of Chemistry and Institute of Materials Science and Engineering, Washington University in St. Louis, St. Louis, MO 63130, USA.
| | - Livia B Pártay
- Department of Chemistry, University of Warwick, Coventry, CV4 7AL, UK
| | - Robert B Wexler
- Department of Chemistry and Institute of Materials Science and Engineering, Washington University in St. Louis, St. Louis, MO 63130, USA.
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4
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An R, Addington CK, Long Y, Rotnicki K, Śliwinska-Bartkowiak M, Thommes M, Gubbins KE. The Nanoscale Wetting Parameter and Its Role in Interfacial Phenomena: Phase Transitions in Nanopores. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2023; 39:18730-18745. [PMID: 38095601 DOI: 10.1021/acs.langmuir.3c01925] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2023]
Abstract
Through analysis of the statistical mechanical equations for a thin adsorbed film (gas, liquid, or solid) on a solid substrate or confined within a pore, it is possible to express the equilibrium thermodynamic properties of the film as a function of just two dimensionless parameters: a nanoscale wetting parameter, αw, and pore width, H*. The wetting parameter, αw, is defined in terms of molecular parameters for the adsorbed film and substrate and so is applicable at the nanoscale and for films of any phase. The main assumptions in the treatment are that (a) the substrate structure is not significantly affected by the adsorbed layer and (b) the diameter of the adsorbate molecules is not very small compared to the spacing of atoms in the solid substrate. We show that different surface geometries of the substrate (e.g., slit, cylindrical, and spherical pores) and various models of wall heterogeneity can be accounted for through a well-defined correction to the wetting parameter; no new dimensionless variables are introduced. Experimental measurements are reported for contact angles for various liquids on several planar substrates and are shown to be closely correlated with the nanoscale wetting parameter. We apply this approach to phase separation in nanopores of various geometries. Molecular simulation results for the phase diagram in confinement, obtained by the flat histogram Monte Carlo method, are reported and are shown to be closely similar to experimental results for capillary condensation, melting, and the triple point. The value of the wetting parameter, αw, is shown to determine the qualitative behavior (e.g., increase vs decrease in the melting temperature, capillary condensation vs evaporation), whereas the pore width determines the magnitude of the confinement effect. The triple point temperature and pressure for the confined phase are always lower than those for the bulk phase for all cases studied.
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Affiliation(s)
- Rong An
- Department of Chemical & Biomolecular Engineering, North Carolina State University, 911 Partners' Way, Raleigh, North Carolina 27695-7905, United States
- School of Materials Science and Engineering/Herbert Gleiter Institute of Nanoscience, Nanjing University of Science and Technology, Nanjing 210094, China
| | - Cody K Addington
- Department of Chemical & Biomolecular Engineering, North Carolina State University, 911 Partners' Way, Raleigh, North Carolina 27695-7905, United States
- U.S. E.P.A., Center for Computational Toxicology & Exposure, Office of Research & Development, Research Triangle Park, North Carolina 27711, United States
| | - Yun Long
- Department of Chemical & Biomolecular Engineering, North Carolina State University, 911 Partners' Way, Raleigh, North Carolina 27695-7905, United States
- College of Computing, Georgia Institute of Technology, 801 Atlantic Drive, Atlanta, Georgia 30318, United States
| | - Konrad Rotnicki
- Faculty of Physics, Adam Mickiewicz University, Umultowska 85, Poznan 61-614, Poland
| | | | - Matthias Thommes
- Department of Chemical & Bioengineering, Friedrich-Alexander Universitaet Erlangen-Nurernberg, Erlangen 91058, Germany
| | - Keith E Gubbins
- Department of Chemical & Biomolecular Engineering, North Carolina State University, 911 Partners' Way, Raleigh, North Carolina 27695-7905, United States
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5
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Robillard AN, Gibson GW, Meyer R. Thermal transport in kinked nanowires through simulation. BEILSTEIN JOURNAL OF NANOTECHNOLOGY 2023; 14:586-602. [PMID: 37228743 PMCID: PMC10204203 DOI: 10.3762/bjnano.14.49] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Accepted: 04/28/2023] [Indexed: 05/27/2023]
Abstract
The thermal conductance of nanowires is an oft-explored quantity, but its dependence on the nanowire shape is not completely understood. The behaviour of the conductance is examined as kinks of varying angular intensity are included into nanowires. The effects on thermal transport are evaluated through molecular dynamics simulations, phonon Monte Carlo simulations and classical solutions of the Fourier equation. A detailed look is taken at the nature of heat flux within said systems. The effects of the kink angle are found to be complex, influenced by multiple factors including crystal orientation, details of transport modelling, and the ratio of mean free path to characteristic system lengths. The effect of varying phonon reflection specularity on the heat flux is also examined. It is found that, in general, the flow of heat through systems simulated through phonon Monte Carlo methods is concentrated into a channel smaller than the wire dimensions, while this is not the case in the classical solutions of the Fourier model.
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Affiliation(s)
- Alexander N Robillard
- Bharti School of Engineering and Computer Science, Laurentian University, Sudbury P3E 2C6, Canada
| | - Graham W Gibson
- Bharti School of Engineering and Computer Science, Laurentian University, Sudbury P3E 2C6, Canada
| | - Ralf Meyer
- Bharti School of Engineering and Computer Science, Laurentian University, Sudbury P3E 2C6, Canada
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6
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Lam J, Pietrucci F. Critical comparison of general-purpose collective variables for crystal nucleation. Phys Rev E 2023; 107:L012601. [PMID: 36797915 DOI: 10.1103/physreve.107.l012601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Accepted: 01/06/2023] [Indexed: 06/18/2023]
Abstract
The nucleation of crystals is a prominent phenomenon in science and technology that still lacks a full atomic-scale understanding. Much work has been devoted to identifying order parameters able to track the process, from the inception of early nuclei to their maturing to critical size until growth of an extended crystal. We critically assess and compare two powerful distance-based collective variables, an effective entropy derived from liquid state theory and the path variable based on permutation invariant vectors using the Kob-Andersen binary mixture and a combination of enhanced-sampling techniques. Our findings reveal a comparable ability to drive nucleation when a bias potential is applied, and comparable free-energy barriers and structural features. Yet, we also found an imperfect correlation with the committor probability on the barrier top which was bypassed by changing the order parameter definition.
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Affiliation(s)
- Julien Lam
- CEMES, Centre National de la Recherche Scientifique and Université de Toulouse, 29 rue Jeanne Marvig, 31055 Toulouse Cedex, France
- Université Lille, Centre National de la Recherche Scientifique, INRA, ENSCL, UMR 8207, UMET, Unité Matériaux et Transformations, F 59000 Lille, France
| | - Fabio Pietrucci
- Sorbonne Université, Centre National de la Recherche Scientifique, UMR 7590, IMPMC, 75005 Paris, France
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7
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van Westen T, Gross J. Double-Hard-Sphere perturbation theory: a perturbation theory that is less dependent on the value of the hard-sphere diameter. Mol Phys 2022. [DOI: 10.1080/00268976.2022.2059410] [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]
Affiliation(s)
- Thijs van Westen
- Institute of Thermodynamics and Thermal Process Engineering, University of Stuttgart, Stuttgart, Germany
| | - Joachim Gross
- Institute of Thermodynamics and Thermal Process Engineering, University of Stuttgart, Stuttgart, Germany
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8
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Heyes DM, Pieprzyk S, Brańka AC. Application of cell models to the melting and sublimation lines of the Lennard-Jones and related potential systems. Phys Rev E 2021; 104:044119. [PMID: 34781546 DOI: 10.1103/physreve.104.044119] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2021] [Accepted: 09/27/2021] [Indexed: 11/07/2022]
Abstract
Harmonic cell models (HCMs) are shown to predict the melting line of the Lennard-Jones (LJ) but not the sublimation line. In addition, even for the melting line, the HCMs are found to be physically unrealistic for inverse power potential systems near the hard-sphere limit, and for the Weeks-Chandler-Andersen system at extremely low temperatures. Despite this, the HCM accurately predicts the LJ mean-square displacement (MSD) from molecular-dynamics (MD) simulations along both lines after simple scaling corrections, to include the effects of anharmonicity and correlated dynamics of the atoms, are applied. Single caged atom molecular dynamics and Monte Carlo simulations provide further quantitative characterization of these additional effects, which go beyond harmonicity. The melting indicator and a modification of the cell model in a similar form are shown to be approximately constant along the melting line, which indicates an isomorph. The less well studied LJ sublimation line is shown not to be an isomorph, yet it still can be represented analytically very accurately by the relationship k_{B}T=aρ^{4}+bρ^{2}, where a and b are constants (k_{B} is Boltzmann's constant, T is the temperature, and ρ is the number density). This relationship has been found previously for the melting line, but the two constants have opposite signs for the sublimation and melting lines. This simple formula is also predicted using a nonharmonic static lattice expression for the pressure. The probability distribution function of the melting factor indicates departures from harmonic or Gaussian behavior in the lower wing. Nevertheless, the mean melting factor is shown to follow a simple MSD Debye-Waller factor dependence along both the melting and sublimation lines. This work combining HCM and MD simulations provides a comparison of the melting and sublimation lines of the LJ system, which could provide the foundations for a more unified statistical mechanical description of these two solid boundary lines.
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Affiliation(s)
- D M Heyes
- Department of Physics, Royal Holloway, University of London, Egham, Surrey TW20 0EX, United Kingdom
| | - S Pieprzyk
- Institute of Molecular Physics, Polish Academy of Sciences, M. Smoluchowskiego 17, 60-179 Poznań, Poland
| | - A C Brańka
- Institute of Molecular Physics, Polish Academy of Sciences, M. Smoluchowskiego 17, 60-179 Poznań, Poland
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9
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Tsai ST, Tiwary P. On the distance between A and B in molecular configuration space. MOLECULAR SIMULATION 2021. [DOI: 10.1080/08927022.2020.1761548] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Affiliation(s)
- Sun-Ting Tsai
- Department of Physics and Institute for Physical Science and Technology, University of Maryland, College Park, MD, USA
| | - Pratyush Tiwary
- Department of Chemistry and Biochemistry and Institute for Physical Science and Technology, University of Maryland, College Park, MD, USA
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10
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Wang X, Ramírez-Hinestrosa S, Dobnikar J, Frenkel D. The Lennard-Jones potential: when (not) to use it. Phys Chem Chem Phys 2020; 22:10624-10633. [PMID: 31681941 DOI: 10.1039/c9cp05445f] [Citation(s) in RCA: 74] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/14/2024]
Abstract
The Lennard-Jones 12-6 potential (LJ) is arguably the most widely used pair potential in molecular simulations. In fact, it is so popular that the question is rarely asked whether it is fit for purpose. In this paper, we argue that, whilst the LJ potential was designed for noble gases such as argon, it is often used for systems where it is not expected to be particularly realistic. Under those circumstances, the disadvantages of the LJ potential become relevant: most important among these is that in simulations the LJ potential is always modified such that it has a finite range. More seriously, there is by now a whole family of different potentials that are all called Lennard-Jones 12-6, and that are all different - and that may have very different macroscopic properties. In this paper, we consider alternatives to the LJ 12-6 potential that could be employed under conditions where the LJ potential is only used as a typical short-ranged potential with attraction. We construct a class of potentials that are, in many respects LJ-like but that are by construction finite ranged, vanishing quadratically at the cut-off distance, and that are designed to be computationally cheap. Below, we present this potential and report numerical data for its thermodynamic and transport properties, for the most important cases (cut-off distance rc = 2σ ("LJ-like") and rc = 1.2σ (a typical "colloidal" potential)).
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Affiliation(s)
- Xipeng Wang
- Institute of Physics, Chinese Academy of Sciences, 8 Third South Street, Zhongguancun, Beijing 100190, China
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11
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Alsaifi NM. Simulation‐based
equations of state for the
Lennard‐Jones
fluid: Apparent success and hidden failure. AIChE J 2020. [DOI: 10.1002/aic.16244] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Nayef M. Alsaifi
- Chemical Engineering DepartmentKing Fahd University of Petroleum & Minerals Dhahran Saudi Arabia
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12
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Ouyang W, Sun B, Sun Z, Xu S. Entire crystallization process of Lennard-Jones liquids: A large-scale molecular dynamics study. J Chem Phys 2020; 152:054903. [DOI: 10.1063/1.5139574] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Affiliation(s)
- Wenze Ouyang
- Key Laboratory of Microgravity (National Microgravity Laboratory), Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190, China
| | - Bin Sun
- School of Materials and Chemical Engineering, Zhongyuan University of Technology, Zhengzhou 450007, China
| | - Zhiwei Sun
- Key Laboratory of Microgravity (National Microgravity Laboratory), Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190, China
| | - Shenghua Xu
- Key Laboratory of Microgravity (National Microgravity Laboratory), Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190, China
- School of Engineering Science, University of Chinese Academy of Sciences, Beijing 100049, China
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13
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Abolala M, Peyvandi K, Varaminian F, Hashemianzadeh SM. Thermodynamic properties of the Lennard-Jones FCC solid: perturbation theory parameterisation and Monte Carlo simulation. Mol Phys 2020. [DOI: 10.1080/00268976.2019.1582813] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Affiliation(s)
- Mostafa Abolala
- Gas Hydrate Research Laboratory, Faculty of Chemical, Gas and Petroleum Engineering, Semnan University, Semnan, Iran
| | - Kiana Peyvandi
- Gas Hydrate Research Laboratory, Faculty of Chemical, Gas and Petroleum Engineering, Semnan University, Semnan, Iran
| | - Farshad Varaminian
- Gas Hydrate Research Laboratory, Faculty of Chemical, Gas and Petroleum Engineering, Semnan University, Semnan, Iran
| | - Seyed Majid Hashemianzadeh
- Molecular Simulation Research Laboratory, Department of Chemistry, Iran University of Science and Technology, Tehran, Iran
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14
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Stephan S, Thol M, Vrabec J, Hasse H. Thermophysical Properties of the Lennard-Jones Fluid: Database and Data Assessment. J Chem Inf Model 2019; 59:4248-4265. [DOI: 10.1021/acs.jcim.9b00620] [Citation(s) in RCA: 55] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Simon Stephan
- Laboratory of Engineering Thermodynamics (LTD), TU Kaiserslautern, 67663 Kaiserslautern, Germany
| | - Monika Thol
- Thermodynamics, Ruhr University Bochum, 44801 Bochum, Germany
| | - Jadran Vrabec
- Thermodynamics and Process Engineering, TU Berlin, 10587 Berlin, Germany
| | - Hans Hasse
- Laboratory of Engineering Thermodynamics (LTD), TU Kaiserslautern, 67663 Kaiserslautern, Germany
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15
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Nakamura K, Ookawa R, Yasuda S. Solidification of the Lennard-Jones fluid near a wall in thermohydrodynamic lubrication. Phys Rev E 2019; 100:033109. [PMID: 31639930 DOI: 10.1103/physreve.100.033109] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2019] [Indexed: 11/07/2022]
Abstract
We investigate the thermohydrodynamic lubrication of the Lennard-Jones (LJ) fluid in plain wall channels by using a molecular-dynamics simulation. It is found that the LJ fluid solidifies near the wall when the viscous heating of the LJ fluid in the bulk regime is sufficiently large. The thickness of the solidified layer increases with the channel width. Thus, a long-range-ordered crystal-like structure forms near the wall in high-speed lubrication when the channel width is large. The mechanism of this counterintuitive solidification is investigated from both macroscopic and microscopic points of view. It is elucidated that the LJ molecules are densely confined in the vicinity of the wall due to the macroscopic mass and heat transport in the bulk regime. In this densely confined regime, the fluid molecules form a crystal-like structure, which is similar to that of the wall molecules, via direct molecular interaction. Band formation is also observed in the solidified region when the channel width is sufficiently large.
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Affiliation(s)
- Kouki Nakamura
- Graduate School of Simulation Studies, University of Hyogo, Kobe 650-0047, Japan
| | - Ryo Ookawa
- Graduate School of Simulation Studies, University of Hyogo, Kobe 650-0047, Japan
| | - Shugo Yasuda
- Graduate School of Simulation Studies, University of Hyogo, Kobe 650-0047, Japan
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16
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Bell IH, Messerly R, Thol M, Costigliola L, Dyre JC. Modified Entropy Scaling of the Transport Properties of the Lennard-Jones Fluid. J Phys Chem B 2019; 123:6345-6363. [PMID: 31241958 DOI: 10.1021/acs.jpcb.9b05808] [Citation(s) in RCA: 53] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Rosenfeld proposed two different scaling approaches to model the transport properties of fluids, separated by 22 years, one valid in the dilute gas, and another in the liquid phase. In this work, we demonstrate that these two limiting cases can be connected through the use of a novel approach to scaling transport properties and a bridging function. This approach, which is empirical and not derived from theory, is used to generate reference correlations for the transport properties of the Lennard-Jones 12-6 fluid of viscosity, thermal conductivity, and self-diffusion. This approach, with a very simple functional form, allows for the reproduction of the most accurate simulation data to within nearly their statistical uncertainty. The correlations are used to confirm that for the Lennard-Jones fluid the appropriately scaled transport properties are nearly monovariate functions of the excess entropy from low-density gases into the supercooled phase and up to extreme temperatures. This study represents the most comprehensive metastudy of the transport properties of the Lennard-Jones fluid to date.
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Affiliation(s)
- Ian H Bell
- Applied Chemicals and Materials Division , National Institute of Standards and Technology , Boulder , Colorado 80305 , United States
| | - Richard Messerly
- Applied Chemicals and Materials Division , National Institute of Standards and Technology , Boulder , Colorado 80305 , United States
| | - Monika Thol
- Thermodynamics , Ruhr-Universität Bochum , Universitätsstraße 150 , 44801 Bochum , Germany
| | - Lorenzo Costigliola
- DNRF Centre "Glass and Time," IMFUFA, Department of Science and Environment , Roskilde University , Postbox 260, DK-4000 Roskilde , Denmark
| | - Jeppe C Dyre
- DNRF Centre "Glass and Time," IMFUFA, Department of Science and Environment , Roskilde University , Postbox 260, DK-4000 Roskilde , Denmark
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17
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Schieber NP, Shirts MR. Configurational mapping significantly increases the efficiency of solid-solid phase coexistence calculations via molecular dynamics: Determining the FCC-HCP coexistence line of Lennard-Jones particles. J Chem Phys 2019; 150:164112. [DOI: 10.1063/1.5080431] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Affiliation(s)
- Natalie P. Schieber
- Department of Chemical and Biological Engineering, University of Colorado Boulder, Boulder, Colorado 80309, USA
| | - Michael R. Shirts
- Department of Chemical and Biological Engineering, University of Colorado Boulder, Boulder, Colorado 80309, USA
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18
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Heat capacity and heat of adsorption at orientational phase transition in nitrogen monolayer on graphite. ADSORPTION 2019. [DOI: 10.1007/s10450-019-00045-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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19
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Schultz AJ, Kofke DA. Comprehensive high-precision high-accuracy equation of state and coexistence properties for classical Lennard-Jones crystals and low-temperature fluid phases. J Chem Phys 2018; 149:204508. [DOI: 10.1063/1.5053714] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Affiliation(s)
- Andrew J. Schultz
- Department of Chemical and Biological Engineering, University at Buffalo, The State University of New York, Buffalo, New York 14260-4200, USA
| | - David A. Kofke
- Department of Chemical and Biological Engineering, University at Buffalo, The State University of New York, Buffalo, New York 14260-4200, USA
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20
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Purohit A, Schultz AJ, Moustafa SG, Errington JR, Kofke DA. Free energy and concentration of crystalline vacancies by molecular simulation. Mol Phys 2018. [DOI: 10.1080/00268976.2018.1481542] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
Affiliation(s)
- Apoorva Purohit
- Department of Chemical and Biological Engineering, University at Buffalo, The State University of New York, Buffalo, NY, USA
| | - Andrew J. Schultz
- Department of Chemical and Biological Engineering, University at Buffalo, The State University of New York, Buffalo, NY, USA
| | - Sabry G. Moustafa
- Department of Chemical and Biological Engineering, University at Buffalo, The State University of New York, Buffalo, NY, USA
| | - Jeffrey R. Errington
- Department of Chemical and Biological Engineering, University at Buffalo, The State University of New York, Buffalo, NY, USA
| | - David A. Kofke
- Department of Chemical and Biological Engineering, University at Buffalo, The State University of New York, Buffalo, NY, USA
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21
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Heidari M, Cortes-Huerto R, Kremer K, Potestio R. Concurrent coupling of realistic and ideal models of liquids and solids in Hamiltonian adaptive resolution simulations. THE EUROPEAN PHYSICAL JOURNAL. E, SOFT MATTER 2018; 41:64. [PMID: 29785645 DOI: 10.1140/epje/i2018-11675-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Accepted: 05/03/2018] [Indexed: 05/27/2023]
Abstract
To understand the properties of a complex system it is often illuminating to perform a comparison with a simpler, even idealised one. A prototypical application of this approach is the calculation of free energies and chemical potentials in liquids, which can be decomposed in the sum of ideal and excess contributions. In the same spirit, in computer simulations it is possible to extract useful information on a given system making use of setups where two models, an accurate one and a simpler one, are concurrently employed and directly coupled. Here, we tackle the issue of coupling atomistic or, more in general, interacting models of a system with the corresponding idealised representations: for a liquid, this is the ideal gas, i.e. a collection of non-interacting particles; for a solid, we employ the ideal Einstein crystal, a construct in which particles are decoupled from one another and restrained by a harmonic, exactly integrable potential. We describe in detail the practical and technical aspects of these simulations, and suggest that the concurrent usage and coupling of realistic and ideal models represents a promising strategy to investigate liquids and solids in silico.
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Affiliation(s)
- Maziar Heidari
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128, Mainz, Germany
| | | | - Kurt Kremer
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128, Mainz, Germany
| | - Raffaello Potestio
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128, Mainz, Germany.
- Physics Department, University of Trento, via Sommarive, 14 I-38123, Trento, Italy.
- INFN-TIFPA, Trento Institute for Fundamental Physics and Applications, I-38123, Trento, Italy.
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22
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Mirzaeinia A, Feyzi F, Hashemianzadeh SM. Equation of state and Helmholtz free energy for the atomic system of the repulsive Lennard-Jones particles. J Chem Phys 2017; 147:214503. [DOI: 10.1063/1.4997256] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Affiliation(s)
- Ali Mirzaeinia
- Thermodynamics Research Laboratory, School of Chemical Engineering, Iran University of Science and Technology, Tehran 16846-13114, Iran
| | - Farzaneh Feyzi
- Thermodynamics Research Laboratory, School of Chemical Engineering, Iran University of Science and Technology, Tehran 16846-13114, Iran
| | - Seyed Majid Hashemianzadeh
- Molecular Simulation Research Laboratory, Department of Chemistry, Iran University of Science and Technology, Tehran 16846-13114, Iran
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23
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Kaneko T. Elevation/depression mechanism of freezing points of liquid confined in slit nanopores. MOLECULAR SIMULATION 2017. [DOI: 10.1080/08927022.2017.1350785] [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)
- Toshihiro Kaneko
- Department of Mechanical Engineering, Tokyo University of Science, Noda, Japan
- Research Institute for Science and Technology (RIST), Tokyo University of Science, Noda, Japan
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24
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Köster A, Mausbach P, Vrabec J. Premelting, solid-fluid equilibria, and thermodynamic properties in the high density region based on the Lennard-Jones potential. J Chem Phys 2017; 147:144502. [DOI: 10.1063/1.4990667] [Citation(s) in RCA: 11] [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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25
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Pártay LB, Ortner C, Bartók AP, Pickard CJ, Csányi G. Polytypism in the ground state structure of the Lennard-Jonesium. Phys Chem Chem Phys 2017; 19:19369-19376. [PMID: 28707687 DOI: 10.1039/c7cp02923c] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We present a systematic study of the stability of nineteen different periodic structures using the finite range Lennard-Jones potential model discussing the effects of pressure, potential truncation, cutoff distance and Lennard-Jones exponents. The structures considered are the hexagonal close packed (hcp), face centred cubic (fcc) and seventeen other polytype stacking sequences, such as dhcp and 9R. We found that at certain pressure and cutoff distance values, neither fcc nor hcp is the ground state structure as previously documented, but different polytypic sequences. This behaviour shows a strong dependence on the way the tail of the potential is truncated.
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Affiliation(s)
- Lívia B Pártay
- Department of Chemistry, University of Reading, Reading RG6 6AD, UK.
| | - Christoph Ortner
- Mathematics Institute, University of Warwick, Coventry CV4 7AL, UK
| | - Albert P Bartók
- STFC Scientific Computing Department, Rutherford Appleton Laboratory, Didcot OX11 0QX, UK
| | - Chris J Pickard
- Department of Materials Science & Metallurgy, University of Cambridge, Cambridge CB3 0FS, UK and Advanced Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba, Sendai, 980-8577, Japan
| | - Gábor Csányi
- Engineering Laboratory, University of Cambridge, Cambridge CB2 1PZ, UK
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26
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Ustinov EA. Efficient chemical potential evaluation with kinetic Monte Carlo method and non-uniform external potential: Lennard-Jones fluid, liquid, and solid. J Chem Phys 2017; 147:014105. [DOI: 10.1063/1.4991324] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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27
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Affiliation(s)
- Rolf Lustig
- Department of Chemical and Biomedical Engineering, Cleveland State University, Cleveland, Ohio, USA
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28
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Moustafa SG, Schultz AJ, Kofke DA. Harmonically Assisted Methods for Computing the Free Energy of Classical Crystals by Molecular Simulation: A Comparative Study. J Chem Theory Comput 2017; 13:825-834. [DOI: 10.1021/acs.jctc.6b01082] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Sabry G. Moustafa
- Department of Chemical and
Biological Engineering, University at Buffalo, The State University of New York, Buffalo, New York 14260-4200, United States
| | - Andrew J. Schultz
- Department of Chemical and
Biological Engineering, University at Buffalo, The State University of New York, Buffalo, New York 14260-4200, United States
| | - David A. Kofke
- Department of Chemical and
Biological Engineering, University at Buffalo, The State University of New York, Buffalo, New York 14260-4200, United States
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29
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Adidharma H, Tan SP. Accurate Monte Carlo simulations on FCC and HCP Lennard-Jones solids at very low temperatures and high reduced densities up to 1.30. J Chem Phys 2016; 145:014503. [DOI: 10.1063/1.4955061] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Hertanto Adidharma
- Department of Petroleum Engineering, University of Wyoming, Laramie, Wyoming 82070, USA
| | - Sugata P. Tan
- Planetary Science Institute, Tucson, Arizona 8471, USA
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30
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Sosso G, Chen J, Cox SJ, Fitzner M, Pedevilla P, Zen A, Michaelides A. Crystal Nucleation in Liquids: Open Questions and Future Challenges in Molecular Dynamics Simulations. Chem Rev 2016; 116:7078-116. [PMID: 27228560 PMCID: PMC4919765 DOI: 10.1021/acs.chemrev.5b00744] [Citation(s) in RCA: 379] [Impact Index Per Article: 47.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Indexed: 11/28/2022]
Abstract
The nucleation of crystals in liquids is one of nature's most ubiquitous phenomena, playing an important role in areas such as climate change and the production of drugs. As the early stages of nucleation involve exceedingly small time and length scales, atomistic computer simulations can provide unique insights into the microscopic aspects of crystallization. In this review, we take stock of the numerous molecular dynamics simulations that, in the past few decades, have unraveled crucial aspects of crystal nucleation in liquids. We put into context the theoretical framework of classical nucleation theory and the state-of-the-art computational methods by reviewing simulations of such processes as ice nucleation and the crystallization of molecules in solutions. We shall see that molecular dynamics simulations have provided key insights into diverse nucleation scenarios, ranging from colloidal particles to natural gas hydrates, and that, as a result, the general applicability of classical nucleation theory has been repeatedly called into question. We have attempted to identify the most pressing open questions in the field. We believe that, by improving (i) existing interatomic potentials and (ii) currently available enhanced sampling methods, the community can move toward accurate investigations of realistic systems of practical interest, thus bringing simulations a step closer to experiments.
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Affiliation(s)
- Gabriele
C. Sosso
- Thomas Young Centre, London
Centre for Nanotechnology and Department of Physics and Astronomy, University College London, Gower Street WC1E
6BT London, U.K.
| | - Ji Chen
- Thomas Young Centre, London
Centre for Nanotechnology and Department of Physics and Astronomy, University College London, Gower Street WC1E
6BT London, U.K.
| | | | - Martin Fitzner
- Thomas Young Centre, London
Centre for Nanotechnology and Department of Physics and Astronomy, University College London, Gower Street WC1E
6BT London, U.K.
| | - Philipp Pedevilla
- Thomas Young Centre, London
Centre for Nanotechnology and Department of Physics and Astronomy, University College London, Gower Street WC1E
6BT London, U.K.
| | - Andrea Zen
- Thomas Young Centre, London
Centre for Nanotechnology and Department of Physics and Astronomy, University College London, Gower Street WC1E
6BT London, U.K.
| | - Angelos Michaelides
- Thomas Young Centre, London
Centre for Nanotechnology and Department of Physics and Astronomy, University College London, Gower Street WC1E
6BT London, U.K.
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31
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Mortazavifar M, Oettel M. A fundamental measure density functional for fluid and crystal phases of the Asakura-Oosawa model. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2016; 28:244018. [PMID: 27116650 DOI: 10.1088/0953-8984/28/24/244018] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
We investigate a density functional for the Asakura-Oosawa model of colloid-polymer mixtures, describing both fluid and crystal phases. It is derived by linearizing the two-component fundamental-measure hard sphere tensor functional in the second (polymer) component. We discuss the formulation of an effective density functional for colloids only. For small polymer-colloid size ratios the effective, polymer-induced potential between colloids is short-range attractive and of two-body form but we show that the effective density functional is not equivalent to standard mean-field approaches where attractions are taken into account by terms second order in the colloid density. We calculate numerically free energies and phase diagrams in good agreement with available simulations, furthermore we discuss the colloid and polymer distributions in the crystal and determine equilibrium vacancy concentrations. Numerical results reveal a fairly strong sensitivity to the specific type of underlying fundamental measure hard sphere functional which could aid further development of fundamental measure theory.
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Affiliation(s)
- Mostafa Mortazavifar
- Institut für Angewandte Physik, Universität Tübingen, Auf der Morgenstelle 10, 72076 Tübingen, Germany
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32
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Calero C, Knorowski C, Travesset A. Determination of anharmonic free energy contributions: Low temperature phases of the Lennard-Jones system. J Chem Phys 2016; 144:124102. [DOI: 10.1063/1.4944069] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- C. Calero
- Center for Polymer Studies and Department of Physics, Boston University, 590 Commonwealth Avenue, Boston, Massachusetts 02215, USA
- Departament de Física Fonamental, Universitat de Barcelona, Martí i Franqués 1, Barcelona 08028, Spain
| | - C. Knorowski
- Department of Physics and Astronomy and Ames Laboratory, Iowa State University, Ames, Iowa 50011, USA
| | - A. Travesset
- Department of Physics and Astronomy and Ames Laboratory, Iowa State University, Ames, Iowa 50011, USA
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33
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Moustafa SG, Schultz AJ, Kofke DA. Very fast averaging of thermal properties of crystals by molecular simulation. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2015; 92:043303. [PMID: 26565360 DOI: 10.1103/physreve.92.043303] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2015] [Indexed: 06/05/2023]
Abstract
Knowledge of approximate harmonic behavior of crystals is introduced into a new "mapped averaging" framework to yield alternative expressions for the thermodynamic properties of crystalline systems. The expressions separate the known harmonic behavior from residual averages, which thus encapsulate anharmonic contributions to the properties. With harmonic contributions removed, direct measurement of these anharmonic contributions by molecular simulation can be accomplished without contamination by noise produced by the already-known harmonic behavior. We show with application to the Lennard-Jones model that first-derivative properties (pressure, energy) can be obtained to a given precision via this harmonically mapped averaging at least 10 times faster than by using conventional averaging, and second-derivative properties (e.g., heat capacity) are obtained at least 100 times faster; in more favorable cases, the speedup exceeds a millionfold. Free-energy calculations are accelerated by 50 to 1000 times. Data obtained using these formulations are rigorous and not subject to any added approximation, and in fact are less sensitive to inaccuracies relating to finite-size effects, potential truncation, equilibration, and similar considerations. Moreover, the approach does not require any alteration in how sampling is performed during the simulation, so it may be used with standard Monte Carlo or molecular dynamics methods. However, the mapped averages do require evaluation of first and second derivatives of the intermolecular potential, for evaluation of first and second thermodynamic-derivative properties, respectively. Apart from its usefulness to simulation, the formalism developed here may constitute a basis for new theoretical treatments of crystals.
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Affiliation(s)
- Sabry G Moustafa
- Department of Chemical and Biological Engineering, University at Buffalo, The State University of New York, Buffalo, New York 14260-4200, USA
| | - Andrew J Schultz
- Department of Chemical and Biological Engineering, University at Buffalo, The State University of New York, Buffalo, New York 14260-4200, USA
| | - David A Kofke
- Department of Chemical and Biological Engineering, University at Buffalo, The State University of New York, Buffalo, New York 14260-4200, USA
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34
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35
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Mithen JP, Sear RP. Computer simulation of epitaxial nucleation of a crystal on a crystalline surface. J Chem Phys 2014; 140:084504. [PMID: 24588182 DOI: 10.1063/1.4866035] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
We present results of computer simulations of crystal nucleation on a crystalline surface, in the Lennard-Jones model. Motivated by the pioneering work of Turnbull and Vonnegut [Ind. Eng. Chem. 44, 1292 (1952)], we investigate the effects of a mismatch between the surface lattice constant and that of the bulk nucleating crystal. We find that the nucleation rate is maximum close to, but not exactly at, zero mismatch. The offset is due to the finite size of the nucleus. In agreement with a number of experiments, we find that even for large mismatches of 10% or more, the formation of the crystal can be epitaxial, meaning that the crystals that nucleate have a fixed orientation with respect to the surface lattice. However, nucleation is not always epitaxial, and loss of epitaxy does affect how the rate varies with mismatch. The surface lattice strongly influences the nucleation rate. We show that the epitaxy observed in our simulations can be predicted using calculations of the potential energy between the surface and the first layer of the nucleating crystal, in the spirit of simple approaches such as that of Hillier and Ward [Phys. Rev. B 54, 14037 (1996)].
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Affiliation(s)
- J P Mithen
- Department of Physics, University of Surrey, Guildford GU2 7XH, United Kingdom
| | - R P Sear
- Department of Physics, University of Surrey, Guildford GU2 7XH, United Kingdom
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36
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KATAOKA Y, YAMADA Y. Phase Diagram for a Lennard-Jones System Obtained through Constant-Pressure Molecular Dynamics Simulations. JOURNAL OF COMPUTER CHEMISTRY-JAPAN 2014. [DOI: 10.2477/jccj.2014-0016] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Yosuke KATAOKA
- 1) Department of Chemical Science and Technology, Faculty of Bioscience and Applied Chemistry, Hosei University, 3-7-2 Kajino-cho, Koganei, Tokyo 184-8584, Japan
| | - Yuri YAMADA
- 2) Division of Liberal Arts, School of Science and Engineering, Tokyo Denki University, Hatoyama, Hiki-gun, Saitama 350-0394, Japan
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37
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KATAOKA Y, YAMADA Y. Phase Diagram of a Lennard-Jones System by Molecular Dynamics Simulations. JOURNAL OF COMPUTER CHEMISTRY-JAPAN 2014. [DOI: 10.2477/jccj.2013-0023] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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38
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Yuan Q, Zhao YP. Wetting on flexible hydrophilic pillar-arrays. Sci Rep 2013; 3:1944. [PMID: 23736041 PMCID: PMC3672886 DOI: 10.1038/srep01944] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2013] [Accepted: 05/20/2013] [Indexed: 01/16/2023] Open
Abstract
Dynamic wetting on the flexible hydrophilic pillar-arrays is studied using large scale molecular dynamics simulations. For the first time, the combined effect of the surface topology, the intrinsic wettability and the elasticity of a solid on the wetting process is taken into consideration. The direction-dependent dynamics of both liquid and pillars, especially at the moving contact line (MCL), is revealed at atomic level. The flexible pillars accelerate the liquid when the liquid approaches, and pin the liquid when the liquid passes. The liquid deforms the pillars, resulting energy dissipation at the MCL. Scaling analysis is performed based on molecular kinetic theory and validated by our simulations. Our results may expand our knowledge of wetting on pillars and assisting the future design of active control of wetting in practical applications.
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Affiliation(s)
- Quanzi Yuan
- State Key Laboratory of Nonlinear Mechanics, Institute of Mechanics, Chinese Academy of Sciences, Beijing, People's Republic of China
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39
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May HO, Mausbach P, Ruppeiner G. Thermodynamic curvature for attractive and repulsive intermolecular forces. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2013; 88:032123. [PMID: 24125229 DOI: 10.1103/physreve.88.032123] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2013] [Indexed: 06/02/2023]
Abstract
The thermodynamic curvature scalar R for the Lennard-Jones system is evaluated in phase space, including vapor, liquid, and solid state. We paid special attention to the investigation of R along vapor-liquid, liquid-solid, and vapor-solid equilibria. Because R is a measure of interaction strength, we traced out the line R=0 dividing the phase space into regions with effectively attractive (R<0) or repulsive (R>0) interactions. Furthermore, we analyzed the dependence of R on the strength of attraction applying a perturbation ansatz proposed by Weeks-Chandler-Anderson. Our results show clearly a transition from R>0 (for poorly repulsive interaction) to R<0 when loading attraction in the intermolecular potential.
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40
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Wang X, Mi J, Zhong C. Density functional theory for crystal-liquid interfaces of Lennard-Jones fluid. J Chem Phys 2013; 138:164704. [DOI: 10.1063/1.4802633] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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41
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42
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Asano Y, Fuchizaki K. Phase diagram of the modified Lennard-Jones system. J Chem Phys 2012; 137:174502. [DOI: 10.1063/1.4764855] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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43
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Sousa JMG, Ferreira AL, Barroso MA. Determination of the solid-fluid coexistence of the n - 6 Lennard-Jones system from free energy calculations. J Chem Phys 2012; 136:174502. [PMID: 22583244 DOI: 10.1063/1.4707746] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The solid-fluid coexistence properties of the n - 6 Lennard-Jones system, n from 7 to 12, are reported. The procedure relies on determining Helmholtz free energy curves as a function of volume for each phase independently, from several NVT simulations, and then connecting it to points of known absolute free energy. For n = 12 this requires connecting the simulated points to states of very low densities on the liquid phase, and to a harmonic crystal for the solid phase, which involves many extra simulations for each temperature. For the reference points of the remaining systems, however, the free energy at a given density and temperature can be calculated relative to the n = 12 system. The method presented here involves a generalization of the multiple histogram method to combine simulations performed with different potentials, provided they visit overlapping regions of the phase space, and allows for a precise calculation of relative free energies. The densities, free energies, average potential energies, pressure, and chemical potential at coexistence are presented for up to T∗ = 5.0 and new estimations of the triple points are given for the n - 6 Lennard-Jones system.
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Affiliation(s)
- J M G Sousa
- Departamento de Física and I3N, Universidade de Aveiro, 3810-193 Aveiro, Portugal
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44
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45
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Moore SG, Wheeler DR. Chemical potential perturbation: extension of the method to lattice sum treatment of intermolecular potentials. J Chem Phys 2012; 136:164503. [PMID: 22559492 DOI: 10.1063/1.4704609] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
The recently developed chemical potential perturbation (CPP) method [S. G. Moore and D. R. Wheeler, J. Chem. Phys. 134, 114514 (2011)] is extended to the lattice (Ewald) sum treatment of intermolecular potentials. The CPP method predicts chemical potentials for a range of composition points using the local (position-dependent) pressure tensor of an inhomogeneous system. When computing the local pressure tensor, one can use the Irving-Kirkwood (IK) or Harasima (H) contours of distributing the pressure. We compare these two contours and show that for a planar interface, the homogeneous pressure and resulting chemical potential can be approximated with the CPP method using either the IK or the H contour, though with the lattice sum method the H contour has much greater computational efficiency. The proposed methods are validated by calculating the chemical potentials of the Lennard-Jones fluid and extended simple point-charge (SPC/E) water, and results show a high level of agreement with respective equations of state.
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Affiliation(s)
- Stan G Moore
- Department of Chemical Engineering, Brigham Young University, 350 CB, Provo, Utah 84602, USA
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46
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Yakub L, Yakub E. Absolute Helmholtz free energy of highly anharmonic crystals: Theory vs Monte Carlo. J Chem Phys 2012; 136:144508. [DOI: 10.1063/1.3702437] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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47
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Schultz AJ, Kofke DA. Algorithm for constant-pressure Monte Carlo simulation of crystalline solids. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2011; 84:046712. [PMID: 22181312 DOI: 10.1103/physreve.84.046712] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/07/2011] [Indexed: 05/31/2023]
Abstract
We describe an alternative method for performing isothermal-isobaric Monte Carlo simulations of crystalline solids. This method uses thermodynamics to estimate appropriate scaling of coordinates relative to their nominal lattice sites in order to increase the probability of acceptance of volume changes. We test this coordinate scaling with three systems: hard spheres, Lennard-Jones spheres, and hard dumbbells. In all cases, we find that the move allows for both a larger step size and faster convergence of calculated properties, in comparison to the conventional algorithm. The improvement is more dramatic for hard potentials, where compressing the system using the conventional algorithm (even a small amount) will almost always cause an overlap.
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Affiliation(s)
- Andrew J Schultz
- Department of Chemical and Biological Engineering, University at Buffalo, The State University of New York, Buffalo, New York 14260-4200, USA.
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48
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Moore SG, Wheeler DR. Chemical potential perturbation: a method to predict chemical potentials in periodic molecular simulations. J Chem Phys 2011; 134:114514. [PMID: 21428639 DOI: 10.1063/1.3561865] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
A new method, called chemical potential perturbation (CPP), has been developed to predict the chemical potential as a function of density in periodic molecular simulations. The CPP method applies a spatially varying external force field to the simulation, causing the density to depend upon position in the simulation cell. Following equilibration the homogeneous (uniform or bulk) chemical potential as a function of density can be determined relative to some reference state after correcting for the effects of the inhomogeneity of the system. We compare three different methods of approximating this correction. The first method uses the van der Waals density gradient theory to approximate the inhomogeneous Helmholtz free energy density. The second method uses the local pressure tensor to approximate the homogeneous pressure. The third method uses the Triezenberg-Zwanzig definition of surface tension to approximate the inhomogeneous free energy density. If desired, the homogeneous pressure and Helmholtz free energy can also be predicted by the new method, as well as binodal and spinodal densities of a two-phase fluid region. The CPP method is tested using a Lennard-Jones (LJ) fluid at vapor, liquid, two-phase, and supercritical conditions. Satisfactory agreement is found between the CPP method and an LJ equation of state. The efficiency of the CPP method is compared to that for Widom's method under the tested conditions. In particular, the new method works well for dense fluids where Widom's method starts to fail.
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Affiliation(s)
- Stan G Moore
- Department of Chemical Engineering, Brigham Young University, 350 CB, Provo, Utah 84602, USA
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Tang Y. A new grand canonical ensemble method to calculate first-order phase transitions. J Chem Phys 2011; 134:224508. [PMID: 21682526 DOI: 10.1063/1.3599048] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
A theory about first-order phase transition of pure fluids is proposed. The theory is developed by combining grand canonical ensemble with density functional for homogeneous fluids. It is based on the fact that the grand partition function of one macroscopic volume is the product of the grand partition functions of its subvolumes. Density fluctuations of molecules determine the relation between the grand partition function and the free energy density. By combining pairs of subvolumes successively, the free energy density is transformed and rapidly becomes stationary. The stationary curve versus molecule density is convex and its linear segments represent phase transitions. The transform leads to the new grand canonical method to calculate phase equilibrium, which is more robust than classic ones. The transform suggests that classical van der Waals loop is physical and essential to phase transition.
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Affiliation(s)
- Yiping Tang
- Honeywell Process Solutions, 300-250 York St., London, Ontario N6A 6K2, Canada.
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Khrapak SA, Morfill GE. Accurate freezing and melting equations for the Lennard-Jones system. J Chem Phys 2011; 134:094108. [PMID: 21384951 DOI: 10.1063/1.3561698] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Analyzing three approximate methods to locate liquid-solid coexistence in simple systems, an observation is made that all of them predict the same functional dependence of the temperature on density at freezing and melting of the conventional Lennard-Jones (LJ) system. The emerging equations can be written as T=Aρ(4)+Bρ(2) in normalized units. We suggest to determine the values of the coefficients A at freezing and melting from the high-temperature limit, governed by the inverse 12th power repulsive potential. The coefficients B can be determined from the triple point parameters of the LJ fluid. This produces freezing and melting equations which are exact in the high-temperature limit and at the triple point and show remarkably good agreement with numerical simulation data in the intermediate region.
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Affiliation(s)
- Sergey A Khrapak
- Max-Planck-Institut für extraterrestrische Physik, D-85741 Garching, Germany.
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