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Falcón-González JM, Contreras-Aburto C, Lara-Peña M, Heinen M, Avendaño C, Gil-Villegas A, Castañeda-Priego R. Assessment of the Wolf method using the Stillinger-Lovett sum rules: From strong electrolytes to weakly charged colloidal dispersions. J Chem Phys 2020; 153:234901. [PMID: 33353329 DOI: 10.1063/5.0033561] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The Ewald method has been the cornerstone in molecular simulations for modeling electrostatic interactions of charge-stabilized many-body systems. In the late 1990s, Wolf and collaborators developed an alternative route to describe the long-range nature of electrostatic interactions; from a computational perspective, this method provides a more efficient and straightforward way to implement long-range electrostatic interactions than the Ewald method. Despite these advantages, the validity of the Wolf potential to account for the electrostatic contribution in charged fluids remains controversial. To alleviate this situation, in this contribution, we implement the Wolf summation method to both electrolyte solutions and charged colloids with moderate size and charge asymmetries in order to assess the accuracy and validity of the method. To this end, we verify that the proper selection of parameters within the Wolf method leads to results that are in good agreement with those obtained through the standard Ewald method and the theory of integral equations of simple liquids within the so-called hypernetted chain approximation. Furthermore, we show that the results obtained with the original Wolf method do satisfy the moment conditions described by the Stillinger-Lovett sum rules, which are directly related to the local electroneutrality condition and the electrostatic screening in the Debye-Hückel regime. Hence, the fact that the solution provided by the Wolf method satisfies the first and second moments of Stillinger-Lovett proves, for the first time, the reliability of the method to correctly incorporate the electrostatic contribution in charge-stabilized fluids. This makes the Wolf method a powerful alternative compared to more demanding computational approaches.
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Affiliation(s)
- José Marcos Falcón-González
- Unidad Profesional Interdisciplinaria de Ingeniería, Campus Guanajuato, Instituto Politécnico Nacional, Av. Mineral de Valenciana No. 200, Col. Fraccionamiento Industrial Puerto Interior, C.P. 36275 Silao de la Victoria, Guanajuato, Mexico
| | - Claudio Contreras-Aburto
- Facultad de Ciencias en Física y Matemáticas, Universidad Autónoma de Chiapas, 29050 Tuxtla Gutiérrez, Mexico
| | - Mayra Lara-Peña
- División de Ciencias e Ingenierías, Campus León, Universidad de Guanajuato, Loma del Bosque 103, Lomas del Campestre, 37150 León, Mexico
| | - Marco Heinen
- División de Ciencias e Ingenierías, Campus León, Universidad de Guanajuato, Loma del Bosque 103, Lomas del Campestre, 37150 León, Mexico
| | - Carlos Avendaño
- Department of Chemical Engineering and Analytical Science, The University of Manchester, Sackville Street, Manchester M13 9PL, United Kingdom
| | - Alejandro Gil-Villegas
- División de Ciencias e Ingenierías, Campus León, Universidad de Guanajuato, Loma del Bosque 103, Lomas del Campestre, 37150 León, Mexico
| | - Ramón Castañeda-Priego
- División de Ciencias e Ingenierías, Campus León, Universidad de Guanajuato, Loma del Bosque 103, Lomas del Campestre, 37150 León, Mexico
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2
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Rodríguez-Rivas A, Romero-Enrique JM, Rull LF. Molecular simulation study of the glass transition in a soft primitive model for ionic liquids. Mol Phys 2019. [DOI: 10.1080/00268976.2019.1674935] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Affiliation(s)
| | - J. M. Romero-Enrique
- Departamento de Física Atómica, Molecular y Nuclear, Area de Física Teórica, Universidad de Sevilla, Sevilla, Spain
| | - L. F. Rull
- Departamento de Física Atómica, Molecular y Nuclear, Area de Física Teórica, Universidad de Sevilla, Sevilla, Spain
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3
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Butlitsky MA, Zelener BB, Zelener BV. Critical point of gas-liquid type phase transition and phase equilibrium functions in developed two-component plasma model. J Chem Phys 2014; 141:024511. [PMID: 25028031 DOI: 10.1063/1.4886403] [Citation(s) in RCA: 8] [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 two-component plasma model, which we called a "shelf Coulomb" model has been developed in this work. A Monte Carlo study has been undertaken to calculate equations of state, pair distribution functions, internal energies, and other thermodynamics properties. A canonical NVT ensemble with periodic boundary conditions was used. The motivation behind the model is also discussed in this work. The "shelf Coulomb" model can be compared to classical two-component (electron-proton) model where charges with zero size interact via a classical Coulomb law. With important difference for interaction of opposite charges: electrons and protons interact via the Coulomb law for large distances between particles, while interaction potential is cut off on small distances. The cut off distance is defined by an arbitrary ɛ parameter, which depends on system temperature. All the thermodynamics properties of the model depend on dimensionless parameters ɛ and γ = βe(2)n(1/3) (where β = 1/kBT, n is the particle's density, kB is the Boltzmann constant, and T is the temperature) only. In addition, it has been shown that the virial theorem works in this model. All the calculations were carried over a wide range of dimensionless ɛ and γ parameters in order to find the phase transition region, critical point, spinodal, and binodal lines of a model system. The system is observed to undergo a first order gas-liquid type phase transition with the critical point being in the vicinity of ɛ(crit) ≈ 13(T(*)(crit) ≈ 0.076), γ(crit) ≈ 1.8(v(*)(crit) ≈ 0.17), P(*)(crit) ≈ 0.39, where specific volume v* = 1/γ(3) and reduced temperature T(*) = ɛ(-1).
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Affiliation(s)
- M A Butlitsky
- Joint Institute for High Temperature of Russian Academy of Science, 125412, Russia, Moscow, Izhorskaya str. 13/2
| | - B B Zelener
- Joint Institute for High Temperature of Russian Academy of Science, 125412, Russia, Moscow, Izhorskaya str. 13/2
| | - B V Zelener
- Joint Institute for High Temperature of Russian Academy of Science, 125412, Russia, Moscow, Izhorskaya str. 13/2
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4
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Coslovich D, Hansen JP, Kahl G. Ultrasoft primitive model of polyionic solutions: Structure, aggregation, and dynamics. J Chem Phys 2011; 134:244514. [DOI: 10.1063/1.3602469] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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5
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Kuzovkov VN, Zvejnieks G, Kotomin EA, Olvera de la Cruz M. Microscopic approach to the kinetics of pattern formation of charged molecules on surfaces. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2010; 82:021602. [PMID: 20866821 DOI: 10.1103/physreve.82.021602] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2010] [Indexed: 05/29/2023]
Abstract
A microscopic formalism based on computing many-particle densities is applied to the analysis of the diffusion-controlled kinetics of pattern formation in oppositely charged molecules on surfaces or adsorbed at interfaces with competing long-range Coulomb and short-range Lennard-Jones interactions. Particular attention is paid to the proper molecular treatment of energetic interactions driving pattern formation in inhomogeneous systems. The reverse Monte Carlo method is used to visualize the spatial molecular distribution based on the calculated radial distribution functions (joint correlation functions). We show the formation of charge domains for certain combinations of temperature and dynamical interaction parameters. The charge segregation evolves into quasicrystalline clusters of charges, due to the competing long- and short-range interactions. The clusters initially co-exist with a gas phase of charges that eventually add to the clusters, generating "fingers" or line of charges of the same sign, very different than the nanopatterns expected by molecular dynamics in systems with competing interactions in two dimensions, such as strain or dipolar versus van der Waals interactions.
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Affiliation(s)
- V N Kuzovkov
- Institute of Solid State Physics, University of Latvia, Riga, Latvia.
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6
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Valeriani C, Camp PJ, Zwanikken JW, van Roij R, Dijkstra M. Computer simulations of the restricted primitive model at very low temperature and density. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2010; 22:104122. [PMID: 21389456 DOI: 10.1088/0953-8984/22/10/104122] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The problem of successfully simulating ionic fluids at low temperature and low density states is well known in the simulation literature: using conventional methods, the system is not able to equilibrate rapidly due to the presence of strongly associated cation-anion pairs. In this paper we present a numerical method for speeding up computer simulations of the restricted primitive model (RPM) at low temperatures (around the critical temperature) and at very low densities (down to 10(-10)σ(-3), where σ is the ion diameter). Experimentally, this regime corresponds to typical concentrations of electrolytes in nonaqueous solvents. As far as we are aware, this is the first time that the RPM has been equilibrated at such extremely low concentrations. More generally, this method could be used to equilibrate other systems that form aggregates at low concentrations.
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Affiliation(s)
- Chantal Valeriani
- SUPA, School of Physics and Astronomy, The University of Edinburgh, Mayfield Road, Edinburgh EH9 3JZ, UK.
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7
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Martín-Betancourt M, Romero-Enrique JM, Rull LF. Liquid−Vapor Coexistence in a Primitive Model for a Room-Temperature Ionic Liquid. J Phys Chem B 2009; 113:9046-9. [DOI: 10.1021/jp903709k] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Marianela Martín-Betancourt
- Departamento de Física Atómica, Molecular y Nuclear, Area de Física Teórica, Universidad de Sevilla, Apartado de Correos 1065, 41080 Sevilla, Spain
| | - José M. Romero-Enrique
- Departamento de Física Atómica, Molecular y Nuclear, Area de Física Teórica, Universidad de Sevilla, Apartado de Correos 1065, 41080 Sevilla, Spain
| | - Luis F. Rull
- Departamento de Física Atómica, Molecular y Nuclear, Area de Física Teórica, Universidad de Sevilla, Apartado de Correos 1065, 41080 Sevilla, Spain
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8
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Hynninen AP, Panagiotopoulos AZ. Simulations of phase transitions and free energies for ionic systems. Mol Phys 2008. [DOI: 10.1080/00268970802112160] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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9
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Whitelam S, Geissler PL. Avoiding unphysical kinetic traps in Monte Carlo simulations of strongly attractive particles. J Chem Phys 2007; 127:154101. [PMID: 17949126 DOI: 10.1063/1.2790421] [Citation(s) in RCA: 134] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
We introduce a "virtual-move" Monte Carlo algorithm for systems of pairwise-interacting particles. This algorithm facilitates the simulation of particles possessing attractions of short range and arbitrary strength and geometry, an important realization being self-assembling particles endowed with strong, short-ranged, and angularly specific ("patchy") attractions. Standard Monte Carlo techniques employ sequential updates of particles and can suffer from low acceptance rates when attractions are strong. In this event, collective motion can be strongly suppressed. Our algorithm avoids this problem by proposing simultaneous moves of collections (clusters) of particles according to gradients of interaction energies. One particle first executes a "virtual" trial move. We determine which of its neighbors move in a similar fashion by calculating individual bond energies before and after the proposed move. We iterate this procedure and update simultaneously the positions of all affected particles. Particles move according to an approximation of realistic dynamics without requiring the explicit computation of forces and without the step size restrictions required when integrating equations of motion. We employ a size- and shape-dependent damping of cluster movements, motivated by collective hydrodynamic effects neglected in simple implementations of Brownian dynamics. We discuss the virtual-move algorithm in the context of other Monte Carlo cluster-move schemes and demonstrate its utility by applying it to a model of biological self-assembly.
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Affiliation(s)
- Stephen Whitelam
- Department of Chemistry, University of California at Berkeley, California 94720, USA.
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10
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Ganzenmüller G, Camp PJ. Vapor-liquid coexistence in fluids of charged hard dumbbells. J Chem Phys 2007; 126:191104. [PMID: 17523784 DOI: 10.1063/1.2738059] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Vapor-liquid coexistence in fluids of charged hard dumbbells, each made up of two oppositely charged hard spheres with diameters sigma and separation d, has been studied using grand-canonical Monte Carlo simulations. In the limit d/sigma-->0, and with the temperature scaled accordingly, the system corresponds to dipolar hard spheres. For separations in the range 0.3<d/sigma<or=1 the coexisting vapor phase contains compact clusters. For separations in the range 0.1<or=d/sigma<0.3 the coexistence is between a chainlike vapor and a networklike liquid. Finite-size effects preclude the simulation of the coexistence in systems with d/sigma<0.1, but extrapolations of the results to d/sigma-->0 yield estimates of the apparent critical parameters for dipolar hard spheres.
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Affiliation(s)
- Georg Ganzenmüller
- School of Chemistry, University of Edinburgh, West Mains Road, Edinburgh EH9 3JJ, United Kingdom
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11
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Avendaño C, Gil-Villegas A. Monte Carlo simulations of primitive models for ionic systems using the Wolf method. Mol Phys 2006. [DOI: 10.1080/00268970600551155] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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12
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Rah K, Freed KF, Dudowicz J, Douglas JF. Lattice model of equilibrium polymerization. V. Scattering properties and the width of the critical regime for phase separation. J Chem Phys 2006; 124:144906. [PMID: 16626244 DOI: 10.1063/1.2181138] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Dynamic clustering associated with self-assembly in many complex fluids can qualitatively alter the shape of phase boundaries and produce large changes in the scale of critical fluctuations that are difficult to comprehend within the existing framework of theories of critical phenomena for nonassociating fluids. In order to elucidate the scattering and critical properties of associating fluids, we consider several models of equilibrium polymerization that describe widely occurring types of associating fluids at equilibrium and that exhibit the well defined cluster geometry of linear polymer chains. Specifically, a Flory-Huggins-type lattice theory is used, in conjunction with the random phase approximation, to compute the correlation length amplitude xi(o) and the Ginzburg number Gi corresponding, respectively, to the scale of composition fluctuations and to a parameter characterizing the temperature range over which Ising critical behavior is exhibited. Our calculations indicate that upon increasing the interparticle association energy, the polymer chains become increasingly long in the vicinity of the critical point, leading naturally to a more asymmetric phase boundary. This increase in the average degree of polymerization implies, in turn, a larger xi(o) and a drastically reduced width of the critical region (as measured by Gi). We thus obtain insight into the common appearance of asymmetric phase boundaries in a wide range of "complex" fluids and into the observation of apparent mean field critical behavior even rather close to the critical point.
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Affiliation(s)
- Kyunil Rah
- The James Franck Institute, The University of Chicago, Chicago, Illinois 60637, USA
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13
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Caballero JB, Puertas AM, Fernández-Barbero A, Javier de Las Nieves F, Romero-Enrique JM, Rull LF. Liquid-gas separation in colloidal electrolytes. J Chem Phys 2006; 124:054909. [PMID: 16468920 DOI: 10.1063/1.2159481] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The liquid-gas transition of an electroneutral mixture of oppositely charged colloids, studied by Monte Carlo simulations, is found in the low-temperature-low-density region. The critical temperature shows a nonmonotonous behavior as a function of the interaction range, kappa(-1), with a maximum at kappasigma approximately 10, implying an island of coexistence in the kappa-rho plane. The system is arranged in such a way that each particle is surrounded by shells of particles with alternating charge. In contrast with the electrolyte primitive model, both neutral and charged clusters are obtained in the vapor phase.
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Affiliation(s)
- José B Caballero
- Group of Complex Fluids Physics, Department of Applied Physics, University of Almeria, 04120 Almeria, Spain
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14
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Zhou W, Percus JK. Size-asymmetric primitive model at low temperature: description of ion pairing and location of the critical point. PHYSICAL REVIEW LETTERS 2005; 95:235701. [PMID: 16384317 DOI: 10.1103/physrevlett.95.235701] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2005] [Indexed: 05/05/2023]
Abstract
We argue that Bjerrum's approach to ion pairing is inappropriate for the size-asymmetric primitive model in the neighborhood of its critical point, and propose a new approach based on the Stillinger-Lovett pairing procedure. The new approach recursively scales up the ion size until linear approximations are suitable for analyzing such a model. To locate the critical point, a residual van der Waals interaction between pairs is added, with an energy cutoff adjusted to match the critical temperature of the restricted primitive model. The locations and downward trends of T(c) and rho(c) with asymmetry are found to compare favorably with simulations.
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Affiliation(s)
- Weimin Zhou
- Department of Physics, New York University, 4 Washington Place, New York, New York 10003, USA
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15
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Kalyuzhnyi YV, Kahl G, Cummings PT. Phase coexistence in a polydisperse charged hard-sphere fluid: Polymer mean spherical approximation. J Chem Phys 2005; 123:124501. [PMID: 16392492 DOI: 10.1063/1.2042347] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
We have reconsidered the phase behavior of a polydisperse mixture of charged hard spheres (CHSs) introducing the concept of minimal size neutral clusters. We thus take into account ionic association effects observed in charged systems close to the phase boundary where the properties of the system are dominated by the presence of neutral clusters while the amount of free ions or charged clusters is negligible. With this concept we clearly pass beyond the simple level of the mean spherical approximation (MSA) that we have presented in our recent study of a polydisperse mixture of CHS [Yu. V. Kalyuzhnyi, G. Kahl, and P. T. Cummings, J. Chem. Phys. 120, 10133 (2004)]. Restricting ourselves to a 1:1 and possibly size-asymmetric model we treat the resulting polydisperse mixture of neutral, polar dimers within the framework of the polymer MSA, i.e., a concept that--similar as the MSA--readily can be generalized from the case of a mixture with a finite number of components to the polydisperse case: again, the model belongs to the class of truncatable free-energy models so that we can map the formally infinitely many coexistence equations onto a finite set of coupled, nonlinear equations in the generalized moments of the distribution function that characterizes the system. This allows us to determine the full phase diagram (in terms of binodals as well as cloud and shadow curves), we can study fractionation effects on the level of the distribution functions of the coexisting daughter phases, and we propose estimates on how the location of the critical point might vary in a polydisperse mixture with an increasing size asymmetry and polydispersity.
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Affiliation(s)
- Yurij V Kalyuzhnyi
- Institute for Condensed Matter Physics, Svientsitskoho 1, 79011 Lviv, Ukraine.
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16
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Van Workum K, Douglas JF. Equilibrium polymerization in the Stockmayer fluid as a model of supermolecular self-organization. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2005; 71:031502. [PMID: 15903430 DOI: 10.1103/physreve.71.031502] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2004] [Indexed: 05/02/2023]
Abstract
A diverse range of molecular self-organization processes arises from a competition between directional and isotropic van der Waals intermolecular interactions. We conduct Monte Carlo simulations of the Stockmayer fluid (SF) with a large dipolar interaction as a minimal self-organization model and focus on basic thermodynamic properties that are needed to characterize the polymerization transition that occurs in this fluid. In particular, we determine the polymerization transition lines from the maximum in the specific heat, C(v), and the inflection point in the extent of polymerization, Phi. We also characterize the geometry (radius of gyration R(g), chain length L, chain topology) of the clusters that form in this associating fluid as a function of temperature, T, and concentration, rho . The pressure, P, and the second virial coefficient, B2, were determined, since these properties contain essential information about the strength of the isotropic (van der Waals) interactions. Our simulations indicate that the locations of the polymerization lines are quantitatively consistent with a model of equilibrium polymerization with the enthalpy of polymerization ("sticking energy") fixed by the minimum in the intermolecular potential. The polymerization transition in the SF is accompanied by a topological transition from predominantly linear to ring polymers upon cooling that is driven by the minimization of the dipolar energy of the clusters. We also find that the basic interaction parameters describing polymerization and phase separation in the SF can be estimated based on the existing theory of equilibrium polymerization, but the theory must be refined to account for ring formation in order to accurately describe the configurational properties of this model self-organizing fluid.
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Affiliation(s)
- Kevin Van Workum
- Polymers Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA.
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17
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Kudlay A, Ermoshkin AV, de la Cruz MO. Phase diagram of charged dumbbells: a random phase approximation approach. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2004; 70:021504. [PMID: 15447493 DOI: 10.1103/physreve.70.021504] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2004] [Indexed: 05/24/2023]
Abstract
The phase diagram of the charged hard dumbbell system (hard spheres of opposite unit charge fixed at contact) is obtained with the use of the random phase approximation (RPA). The effect of the impenetrability of charged spheres on charge-charge fluctuations is described by introduction of a modified electrostatic potential. The correlations of ions in a pair are included via a correlation function in the RPA. The coexistence curve is in good agreement with Monte Carlo simulations. The relevance of the theory to the restricted primitive model is discussed.
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Affiliation(s)
- Alexander Kudlay
- Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, USA
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18
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Caballero JB, Puertas AM, Fernández-Barbero A, de las Nieves FJ. Oppositely charged colloidal binary mixtures: A colloidal analog of the restricted primitive model. J Chem Phys 2004; 121:2428-35. [PMID: 15260798 DOI: 10.1063/1.1767995] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The equilibrium phase diagram of a colloidal system composed of 1:1 mixture of positive and negative particles with equal charge is studied by means of Monte Carlo simulations. The system is the colloidal analog of the restricted primitive model (RPM) for ionic fluids. A liquid-gas transition is found in the low-temperature-low-density region, similar to the liquid-gas transition in the RPM. The fluid-crystal transition is also studied, and the liquid phase is shown to be stable in a narrow range of temperatures. In the liquid, the pair distribution function shows alternating layers of particles with opposite sign of charge surrounding every particle. In the vapor phase, clusters of particles are observed, again in agreement with the RPM. However, a decreasing distribution of clusters is obtained, instead of the discrimination between charged and neutral clusters found in the RPM.
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Affiliation(s)
- José B Caballero
- Group of Complex Fluids Physics, Department of Applied Physics, University of Almeria, 04120, Spain
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19
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Vlachy V, Dominguez H, Pizio O. Temperature Effects in Adsorption of a Primitive Model Electrolyte in Disordered Quenched Media: Predictions of the Replica OZ/HNC Approximation. J Phys Chem B 2003. [DOI: 10.1021/jp035166b] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- V. Vlachy
- Faculty of Chemistry and Chemical Technology, University of Ljubljana, Aškerčeva 5, 1000 Ljubljana, Slovenia, and Instituto de Quımica de la UNAM, Circuito Exterior, Coyoacán 04510, México D.F
| | - H. Dominguez
- Faculty of Chemistry and Chemical Technology, University of Ljubljana, Aškerčeva 5, 1000 Ljubljana, Slovenia, and Instituto de Quımica de la UNAM, Circuito Exterior, Coyoacán 04510, México D.F
| | - O. Pizio
- Faculty of Chemistry and Chemical Technology, University of Ljubljana, Aškerčeva 5, 1000 Ljubljana, Slovenia, and Instituto de Quımica de la UNAM, Circuito Exterior, Coyoacán 04510, México D.F
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20
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Cheong DW, Panagiotopoulos AZ. Critical parameters of unrestricted primitive model electrolytes with charge asymmetries up to 10:1. J Chem Phys 2003. [DOI: 10.1063/1.1612473] [Citation(s) in RCA: 34] [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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21
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Daub CD, Patey GN, Camp PJ. Liquid–vapor criticality in a fluid of charged hard dumbbells. J Chem Phys 2003. [DOI: 10.1063/1.1609192] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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22
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Jiménez-Ángeles F, Messina R, Holm C, Lozada-Cassou M. Ion pairing in model electrolytes: A study via three-particle correlation functions. J Chem Phys 2003. [DOI: 10.1063/1.1596912] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
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23
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Wagner M, Stanga O, Schröer W. Corresponding states analysis of the critical points in binary solutions of room temperature ionic liquids. Phys Chem Chem Phys 2003. [DOI: 10.1039/b305959f] [Citation(s) in RCA: 121] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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24
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Moghaddam S, Panagiotopoulos AZ. Lattice discretization effects on the critical parameters of model nonpolar and polar fluids. J Chem Phys 2003. [DOI: 10.1063/1.1562613] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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