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Zhou S, Panse KS, Motevaselian MH, Aluru NR, Zhang Y. Three-Dimensional Molecular Mapping of Ionic Liquids at Electrified Interfaces. ACS NANO 2020; 14:17515-17523. [PMID: 33227191 DOI: 10.1021/acsnano.0c07957] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Electric double layers (EDLs), occurring ubiquitously at solid-liquid interfaces, are critical for electrochemical energy conversion and storage processes such as capacitive charging and redox reactions. However, to date the molecular-scale structure of EDLs remains elusive. Here we report an advanced technique, electrochemical three-dimensional atomic force microscopy (EC-3D-AFM), and use it to directly image the molecular-scale EDL structure of an ionic liquid under different electrode potentials. We observe not only multiple discrete ionic layers in the EDL on a graphite electrode but also a quasi-periodic molecular density distribution within each layer. Furthermore, we find pronounced 3D reconfiguration of the EDL at different voltages, especially in the first layer. Combining the experimental results with molecular dynamics simulations, we find potential-dependent molecular redistribution and reorientation in the innermost EDL layer, both of which are critical to EDL capacitive charging. We expect this mechanistic understanding to have profound impacts on the rational design of electrode-electrolyte interfaces for energy conversion and storage.
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Affiliation(s)
- Shan Zhou
- Department of Materials Science and Engineering, University of Illinois, Urbana, Illinois 61801, United States
- Materials Research Laboratory, University of Illinois, Urbana, Illinois 61801, United States
| | - Kaustubh S Panse
- Department of Materials Science and Engineering, University of Illinois, Urbana, Illinois 61801, United States
- Materials Research Laboratory, University of Illinois, Urbana, Illinois 61801, United States
| | | | - Narayana R Aluru
- Department of Mechanical Science and Engineering, University of Illinois, Urbana, Illinois 61801, United States
| | - Yingjie Zhang
- Department of Materials Science and Engineering, University of Illinois, Urbana, Illinois 61801, United States
- Materials Research Laboratory, University of Illinois, Urbana, Illinois 61801, United States
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Motevaselian MH, Aluru NR. Universal Reduction in Dielectric Response of Confined Fluids. ACS NANO 2020; 14:12761-12770. [PMID: 32966055 DOI: 10.1021/acsnano.0c03173] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Dielectric permittivity is central to many biological and physiochemical systems, as it affects the long-range electrostatic interactions. Similar to many fluid properties, confinement greatly alters the dielectric response of polar liquids. Many studies have focused on the reduction of the dielectric response of water under confinement. Here, using molecular dynamics simulations, statistical-mechanical theories, and multiscale methods, we study the out-of-plane (z-axis) dielectric response of protic and aprotic fluids confined inside slit-like graphene channels. We show that the reduction in perpendicular permittivity is universal for all the fluids and exhibits a Langevin-like behavior as a function of channel width. We show that this reduction is due to the favorable in-plane (x-y plane) dipole-dipole electrostatic interactions of the interfacial fluid layer. Furthermore, we observe an anomalously low dielectric response under an extreme confinement.
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Affiliation(s)
- Mohammad H Motevaselian
- Department of Mechanical Science and Engineering, Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Narayana R Aluru
- Department of Mechanical Science and Engineering, Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
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3
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Ploetz EA, Smith PE. Gas or Liquid? The Supercritical Behavior of Pure Fluids. J Phys Chem B 2019; 123:6554-6563. [DOI: 10.1021/acs.jpcb.9b04058] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Elizabeth A. Ploetz
- Department of Chemistry, Kansas State University, 213 CBC Building, 1212 Mid Campus Dr. North, Manhattan, Kansas 66506-0401, United States
| | - Paul E. Smith
- Department of Chemistry, Kansas State University, 213 CBC Building, 1212 Mid Campus Dr. North, Manhattan, Kansas 66506-0401, United States
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Sindt JO, Alexander AJ, Camp PJ. Effects of nanoparticle heating on the structure of a concentrated aqueous salt solution. J Chem Phys 2018; 147:214506. [PMID: 29221397 DOI: 10.1063/1.5002002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The effects of a rapidly heated nanoparticle on the structure of a concentrated aqueous salt solution are studied using molecular dynamics simulations. A diamond-like nanoparticle of radius 20 Å is immersed in a sodium-chloride solution at 20% above the experimental saturation concentration and equilibrated at T = 293 K and P = 1 atm. The nanoparticle is then rapidly heated to several thousand degrees Kelvin, and the system is held under isobaric-isoenthalpic conditions. It is observed that after 2-3 ns, the salt ions are depleted far more than water molecules from a proximal zone 15-25 Å from the nanoparticle surface. This leads to a transient reduction in molality in the proximal zone and an increase in ion clustering in the distal zone. At longer times, ions begin to diffuse back into the proximal zone. It is speculated that the formation of proximal and distal zones, and the increase in ion clustering, plays a role in the mechanism of nonphotochemical laser-induced nucleation.
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Affiliation(s)
- Julien O Sindt
- School of Engineering, University of Edinburgh, Mayfield Road, Edinburgh EH9 3JL, Scotland
| | - Andrew J Alexander
- School of Chemistry, University of Edinburgh, David Brewster Road, Edinburgh EH9 3FJ, Scotland
| | - Philip J Camp
- School of Chemistry, University of Edinburgh, David Brewster Road, Edinburgh EH9 3FJ, Scotland
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Demerdash O, Wang L, Head‐Gordon T. Advanced models for water simulations. WILEY INTERDISCIPLINARY REVIEWS-COMPUTATIONAL MOLECULAR SCIENCE 2017. [DOI: 10.1002/wcms.1355] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Omar Demerdash
- Kenneth S. Pitzer Center for Theoretical Chemistry University of California Berkeley CA USA
- Department of Chemistry University of California Berkeley CA USA
| | - Lee‐Ping Wang
- Department of Chemistry University of California, Davis Davis CA USA
| | - Teresa Head‐Gordon
- Kenneth S. Pitzer Center for Theoretical Chemistry University of California Berkeley CA USA
- Department of Chemistry University of California Berkeley CA USA
- Department of Bioengineering University of California Berkeley CA USA
- Department of Chemical and Biomolecular Engineering University of California Berkeley CA USA
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Dufal S, Lafitte T, Haslam AJ, Galindo A, Clark GN, Vega C, Jackson G. The A in SAFT: developing the contribution of association to the Helmholtz free energy within a Wertheim TPT1 treatment of generic Mie fluids. Mol Phys 2015. [DOI: 10.1080/00268976.2015.1029027] [Citation(s) in RCA: 77] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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7
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Bingham R, Ballone P. Energy, structure and vibrational modes of small water clusters by a simple many-body potential mimicking polarisation effects. Mol Phys 2013. [DOI: 10.1080/00268976.2013.831142] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Rana MK, Chandra A. Solvation structure of nanoscopic hydrophobic solutes in supercritical water: Results for varying thickness of hydrophobic walls, solute–solvent interaction and solvent density. Chem Phys 2012. [DOI: 10.1016/j.chemphys.2012.09.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Chialvo AA, Horita J. Polarization behavior of water in extreme aqueous environments: A molecular dynamics study based on the Gaussian charge polarizable water model. J Chem Phys 2010; 133:074504. [PMID: 20726649 DOI: 10.1063/1.3469769] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
We study the polarization behavior of water under geologically relevant extreme aqueous environments along four equidistant supercritical isotherms, 773<or=T(K)<or=1373, and over a wide pressure range, 0<P(GPa)<or=30, by isobaric-isothermal molecular dynamics simulations of the Gaussian charge polarizable water model, to unravel and discuss the underlying link between two precisely defined orientational order parameters and the magnitude of the average induced dipole moment of water. The predicted behavior indicates an isothermal linear dependence (a) between the magnitude of the average induced dipole moment mu(ind) and the average system density rho, (b) between the magnitude of the average induced dipole mu(ind) and that of the total dipole mu(tot), resulting from (c), a compensating (inverse) dependence between the permanent-to-induced dipolar angle theta and the magnitude of the average induced dipole moment mu(ind). Moreover, we interpret this behavior in terms of the evolution of the state dependent tetrahedral order parameter q(T) and the corresponding bond-order parameter Q(6), supplemented by the microstructural analysis based on the three site-site radial distribution functions of water and the distance-ranked nearest-neighbor distributions. Finally, we show that while water exhibits a dramatic microstructural transformation from an open four-coordinated hydrogen-bonded network at normal conditions to a quasi-close-packed coordination, it still preserves a significant degree of hydrogen bonding.
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Affiliation(s)
- Ariel A Chialvo
- Chemical Sciences Division Geochemistry and Interfacial Science Group, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6110, USA.
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Ved’ OV, Gurina DL, Antipova ML, Petrenko VE. Hydrogen bond and dipole moment in sub- and supercritical water close to the saturation curve. RUSSIAN JOURNAL OF PHYSICAL CHEMISTRY A 2010. [DOI: 10.1134/s0036024410080157] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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KOLAFA JIŘÍ, NEZBEDA IVO. Effect of short and long range forces on the structure of water. II. Orientational ordering and the dielectric constant. Mol Phys 2009. [DOI: 10.1080/00268970009483356] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Affiliation(s)
- JIŘÍ KOLAFA
- a E. Hála Laboratory of Thermodynamics , Institute of Chemical Process Fundamentals, Academy of Sciences , 165 02 Prague 6—Suchdol, Czech Republic
| | - IVO NEZBEDA
- a E. Hála Laboratory of Thermodynamics , Institute of Chemical Process Fundamentals, Academy of Sciences , 165 02 Prague 6—Suchdol, Czech Republic
- b Department of Physics , J. E. Purkyně University , 400 96 Ústí n. Lab., Czech Republic
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Martí J, Sala J, Guàrdia E, Gordillo MC. Molecular dynamics simulations of supercritical water confined within a carbon-slit pore. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2009; 79:031606. [PMID: 19391953 DOI: 10.1103/physreve.79.031606] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2008] [Indexed: 05/12/2023]
Abstract
We report the results of a series of molecular dynamics simulations of water inside a carbon-slit pore at supercritical conditions. A range of densities corresponding from liquid (0.66gcm;{-3}) to gas environments (0.08gcm;{-3}) at the supercritical temperature of 673K were considered. Our findings are compared with previous studies of liquid water confined in graphene nanochannels at ambient and high temperatures, and indicate that the microscopic structure of water evolves from hydrogen bond networks characteristic of hot dense liquids to looser arrangements where the dominant units are water monomers and dimers. Water permittivity was found to be very small at low densities, with a tendency to grow with density and to reach typical values of unconfined supercritical water at 0.66gcm;{-3}) . In supercritical conditions, the residence time of water at interfaces is roughly similar to that of water in the central regions of the slabs, if the size of the considered region is taken into account. That time span is long enough to compute dynamical properties such as diffusion or spectral densities. Water diffusion in supercritical states is much faster at low densities, and it is produced in such a way that, at interfaces, translational diffusion is mainly produced along planes parallel to the carbon walls. Spectral frequency shifts depend on several factors, being temperature and density effects the most relevant. However, we can observe corrections due to confinement, important both at the graphene interface and in the central region of the water slab.
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Affiliation(s)
- J Martí
- Departament de Física i Enginyeria Nuclear, Universitat Politècnica de Catalunya, B4-B5 Campus Nord, 08034 Barcelona, Catalonia, Spain.
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Fedotova MV. Structural parameters of RbBr aqueous solution under nearcritical and supercritical conditions with close densities (∼0.65 g/cm3). RUSSIAN JOURNAL OF PHYSICAL CHEMISTRY A 2009. [DOI: 10.1134/s0036024409120334] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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16
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Chialvo AA, Chialvo S, Simonson JM, Kalyuzhnyi YV. Solvation phenomena in dilute multicomponent solutions I. Formal results and molecular outlook. J Chem Phys 2008; 128:214512. [DOI: 10.1063/1.2931942] [Citation(s) in RCA: 9] [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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Yoshida K, Matubayasi N, Nakahara M. Solvation shell dynamics studied by molecular dynamics simulation in relation to the translational and rotational dynamics of supercritical water and benzene. J Chem Phys 2008; 127:174509. [PMID: 17994829 DOI: 10.1063/1.2780871] [Citation(s) in RCA: 22] [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 solvation shell dynamics of supercritical water is analyzed by molecular dynamics simulation with emphasis on its relationship to the translational and rotational dynamics. The relaxation times of the solvation number (tau S), the velocity autocorrelation function (tau D), the angular momentum correlation function (tau J), and the second-order reorientational correlation function (tau 2R) are studied at a supercritical temperature of 400 degrees C over a wide density region of 0.01-1.5 g cm(-3). The relaxation times are decomposed into those conditioned by the solvation number n, and the effect of the short-ranged structure is examined in terms of its probability Pn of occurrence. In the low to medium-density range of 0.01-0.4 g cm(-3), the time scales of water dynamics are in the following sequence: tau D>tau S approximately or > tau J approximately or > tau 2R. This means that the rotation in supercritical water is of the "in-shell" type while the translational diffusion is not. The comparison to supercritical benzene is also performed and the effect of hydrogen bonding is examined. The water diffusion is not of the in-shell type up to the ambient density of 1.0 g cm(-3), which corresponds to the absence of the transition from the collision to the Brownian picture, whereas such transition is present in the case of benzene. The absence of the transition in water comes from the fast reorganization of the hydrogen bonds and the enhanced mobility of the solvation shell in supercritical conditions.
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Affiliation(s)
- Ken Yoshida
- Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan
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Li J, Zhou Z, Sadus RJ. Role of nonadditive forces on the structure and properties of liquid water. J Chem Phys 2007; 127:154509. [PMID: 17949175 DOI: 10.1063/1.2786449] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The role of nonadditive interactions on the structure and dielectric properties of water is investigated at different temperatures using molecular dynamics. A new intermolecular potential is developed which contains an ab initio description of two-body additive interactions plus nonadditive contributions from both three-body interactions and polarization. Polarization is the main nonadditive influence, resulting in improved agreement with experiment for the radial distribution function, dielectric constant, and dipole moment. A comparison is also made with other widely used intermolecular potentials. The new potential provides a superior prediction of the dielectric constant and dipole moment. It also predicts the relative contribution of hydrogen bonding better than the SPC/E potential [Berendsen et al., J. Phys. Chem. 91, 6269 (1987)].
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Affiliation(s)
- Jianhui Li
- Centre for Molecular Simulation, Swinburne University of Technology, P.O. Box 218, Hawthorn, Victoria 3122, Australia
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Raabe G, Sadus RJ. Influence of bond flexibility on the vapor-liquid phase equilibria of water. J Chem Phys 2007; 126:044701. [PMID: 17286493 DOI: 10.1063/1.2428302] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The authors performed Gibbs ensemble simulations on the vapor-liquid equilibrium of water to investigate the influence of incorporating intramolecular degrees of freedom in the simple point charge (SPC) water model. Results for vapor pressures, saturation densities, heats of vaporization, and the critical point for two different flexible models are compared with data for the corresponding rigid SPC and SPC/E models. They found that the introduction of internal vibrations, and also their parametrization, has an observable effect on the prediction of the vapor-liquid coexistence curve. The flexible SPC/Fw model, although optimized to describe bulk diffusion and dielectric constants at ambient conditions, gives the best prediction of saturation densities and the critical point of the examined models.
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Affiliation(s)
- Gabriele Raabe
- Institut für Thermodynamik, Technische Universität Braunschweig, Hans-Sommer-Stasse 5, 38106 Braunschweig, Germany.
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Yoshida K, Matubayasi N, Nakahara M. Self-diffusion of supercritical water in extremely low-density region. J Chem Phys 2006; 125:074307. [PMID: 16942339 DOI: 10.1063/1.2333511] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
The self-diffusion coefficient D for super- and subcritical water is determined by using the proton pulsed-field-gradient spin echo method at high temperatures and low densities. The density of water is ranged in the steamlike region from 0.0041 to 0.0564 g [corrected] cm(-3) at a supercritical temperature of 400 degrees C, also at 0.0041-0.0079 and 0.0041-0.0462 g [corrected] cm(-3) (the steam-branch densities on the coexistence curve and lower) at 200 and 300 degrees C, respectively. The density is precisely determined on the basis of the PVT dependence of the proton chemical shift. The density-diffusivity products in the zero-density limit divided by the square root of the temperature, (rho D)0/square root of T, are 0.94, 1.17, and 1.35 mg m(-1) s(-1) K(-1/2) (mg=10(-3)g) [corrected] at 200, 300, and 400 degrees C, respectively. The (rhoD)0/square root of T obtained decreases with decreasing temperature and is significantly smaller than the temperature-independent value from the hard sphere model, 1.95 mg [corrected] m(-1) s(-1) K(-1/2). The marked temperature dependence reflects the presence of the strong attractive interaction between a pair of water molecules. The magnitude of the experimental D values and the temperature dependence are well reproduced by the molecular dynamics simulation using TIP4P-FQ model. The initial slope of the product rhoD/square root of T against rho is slightly negative at 300 and 400 [corrected] degrees C.
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Affiliation(s)
- Ken Yoshida
- Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan
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21
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Jedlovszky P, Předota M, Nezbeda I. Hydration of apolar solutes of varying size: a systematic study. Mol Phys 2006. [DOI: 10.1080/00268970600761101] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Firouzi M, Sahimi M, Tsotsis TT. Supercritical fluids in porous composite materials: direction-dependent flow properties. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2006; 73:036312. [PMID: 16605656 DOI: 10.1103/physreve.73.036312] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2005] [Revised: 10/18/2005] [Indexed: 05/08/2023]
Abstract
The results of extensive nonequilibrium molecular dynamics simulations of flow and transport of a pure fluid, as well as a binary fluid mixture, through a porous material composed of a macropore, a mesopore, and a nanopore, in the presence of an external pressure gradient, are reported. We find that under supercritical conditions, unusual phenomena occur that give rise to direction-dependent and pressure-dependent permeabilities for the fluids' components. The results, which are also in agreement with a continuum formulation of the problem, indicate that the composite nature of the material, coupled with condensation, give rise to the direction-dependent permeabilities. Therefore, modeling flow and transport of fluids, in the supercritical regime, in porous materials with the type of morphology considered in this paper (such as supported porous membranes) would require using effective permeabilities that depend on both the external pressure drop and the direction along which it is applied to the materials.
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Affiliation(s)
- Mahnaz Firouzi
- Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, CA 90089-1211, USA
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Wierzchowski SJ, Fang ZH, Kofke DA, Tilson JL. Three-body effects in hydrogen fluoride: survey of potential energy surfaces. Mol Phys 2006. [DOI: 10.1080/00268970500424321] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Plugatyr A, Nahtigal I, Svishchev IM. Spatial hydration structures and dynamics of phenol in sub- and supercritical water. J Chem Phys 2006; 124:024507. [PMID: 16422611 DOI: 10.1063/1.2145751] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
The hydration structures and dynamics of phenol in aqueous solution at infinite dilution are investigated using molecular-dynamics simulation technique. The simulations are performed at several temperatures along the coexistence curve of water up to the critical point, and above the critical point with density fixed at 0.3 g/cm3. The hydration structures of phenol are characterized using the radial, cylindrical, and spatial distribution functions. In particular, full spatial maps of local atomic (solvent) density around a solute molecule are presented. It is demonstrated that in addition to normal H bonds with hydroxyl group of phenol, water forms pi-type complexes with the center of the benzene ring, in which H2O molecules act as H-bond donor. At ambient conditions phenol is solvated by 38 water molecules, which make up a large hydrophobic cavity, and forms on average 2.39 H bonds (1.55 of which are due to the hydroxyl group-water interactions and 0.84 are due to the pi complex) with its hydration shell. As temperature increases, the hydration structure of phenol undergoes significant changes. The disappearance of the pi-type H bonding is observed near the critical point. Self-diffusion coefficients of water and phenol are also calculated. Dramatic increase in the diffusivity of phenol in aqueous solution is observed near the critical point of simple point-charge-extended water and is related to the changes in water structure at these conditions.
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Affiliation(s)
- Andriy Plugatyr
- Department of Chemistry, Trent University, Peterborough, Ontario K9J 7B8, Canada
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ChIalvo AA, Horita J. Vapor–liquid equilibria and thermophysical behavior of the SPC-HW model for heavy water. MOLECULAR SIMULATION 2005. [DOI: 10.1080/08927020500412508] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Yoshida K, Wakai C, Matubayasi N, Nakahara M. A new high-temperature multinuclear-magnetic-resonance probe and the self-diffusion of light and heavy water in sub- and supercritical conditions. J Chem Phys 2005; 123:164506. [PMID: 16268711 DOI: 10.1063/1.2056542] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
A high-resolution nuclear-magnetic-resonance probe (500 MHz for 1H) has been developed for multinuclear pulsed-field-gradient spin-echo diffusion measurements at high temperatures up to 400 degrees C. The convection effect on the self-diffusion measurement is minimized by achieving the homogeneous temperature distributions of +/-1 and +/-2 degrees C, respectively, at 250 and 400 degrees C. The high temperature homogeneity is attained by using the solid-state heating system composed of a ceramic (AlN) with high thermal conductivity comparable with that of metal aluminium. The self-diffusion coefficients D for light (1H2O) and heavy (2H2O) water are distinguishably measured at subcritical temperatures of 30-350 degrees C with intervals of 10-25 degrees C on the liquid-vapor coexisting curve and at a supercritical temperature of 400 degrees C as a function of water density between 0.071 and 0.251 gcm3. The D value obtained for 1H2O is 10%-20% smaller than those previously reported because of the absence of the convection effect. At 400 degrees C, the D value for 1H2O is increased by a factor of 3.7 as the water density is reduced from 0.251 to 0.071 gcm3. The isotope ratio D(1H2O)D(2H2O) decreases from 1.23 to approximately 1.0 as the temperature increases from 30 to 400 degrees C. The linear hydrodynamic relationship between the self-diffusion coefficient divided by the temperature and the inverse viscosity does not hold. The effective hydrodynamic radius of water is not constant but increases with the temperature elevation in subcritical water.
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Affiliation(s)
- Ken Yoshida
- Institute for Chemical Research, Kyoto University, Uji, Kyoto 611-0011, Japan
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27
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Li B, Hakuta Y, Hayashi H. Hydrothermal synthesis of KNbO3 powders in supercritical water and its nonlinear optical properties. J Supercrit Fluids 2005. [DOI: 10.1016/j.supflu.2005.02.005] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Kunor TR, Taraphder S. Molecular dynamics study of the density and temperature dependence of bridge functions in normal and supercritical Lennard-Jones fluids. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2005; 72:031201. [PMID: 16241418 DOI: 10.1103/physreve.72.031201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2005] [Revised: 07/12/2005] [Indexed: 05/05/2023]
Abstract
A systematic study of the density and temperature dependence of bridge functions has been carried out using molecular dynamics simulation studies in one-component Lennard-Jones fluids. In deriving the liquid structure, approximate closures are generally used in integral equation theories of liquids to obtain static density correlations. In the present work, we have directly compared the simulated bridge function to two such commonly used closures, viz., hybrid mean spherical approximation (HMSA) [J. Chem. Phys. 84, 2336 (1986)] and Duh-Henderson [J. Chem. Phys. 104, 6742 (1996)] closures with thermodynamic parameters varying from the normal liquid to the supercritical fluid phase far from and near the critical point. In the normal liquid region, both closures show a qualitative agreement with the simulated bridge function, although the extent of correlation at distances sigma < r < or = 2.5sigma is generally underestimated. A similar behavior is obtained in supercritical fluids far from the critical point where critical fluctuations are no longer important. In contrast, significant deviations are observed in the bridge functions in supercritical fluids near the critical point even at densities as small as 25% or 50% of the critical density. Such behavior appears to have resulted from competing contributions to the bridge function from decreasing indirect correlations and small yet significant cavity correlations persistent even at very low densities.
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Affiliation(s)
- Tapas R Kunor
- Department of Chemistry, Indian Institute of Technology, Kharagpur 721302, India.
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Paricaud P, Predota M, Chialvo AA, Cummings PT. From dimer to condensed phases at extreme conditions: Accurate predictions of the properties of water by a Gaussian charge polarizable model. J Chem Phys 2005; 122:244511. [PMID: 16035786 DOI: 10.1063/1.1940033] [Citation(s) in RCA: 191] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Water exhibits many unusual properties that are essential for the existence of life. Water completely changes its character from ambient to supercritical conditions in a way that makes it possible to sustain life at extreme conditions, leading to conjectures that life may have originated in deep-sea vents. Molecular simulation can be very useful in exploring biological and chemical systems, particularly at extreme conditions for which experiments are either difficult or impossible; however this scenario entails an accurate molecular model for water applicable over a wide range of state conditions. Here, we present a Gaussian charge polarizable model (GCPM) based on the model developed earlier by Chialvo and Cummings [Fluid Phase Equilib. 150, 73 (1998)] which is, to our knowledge, the first that satisfies the water monomer and dimer properties, and simultaneously yields very accurate predictions of dielectric, structural, vapor-liquid equilibria, and transport properties, over the entire fluid range. This model would be appropriate for simulating biological and chemical systems at both ambient and extreme conditions. The particularity of the GCPM model is the use of Gaussian distributions instead of points to represent the partial charges on the water molecules. These charge distributions combined with a dipole polarizability and a Buckingham exp-6 potential are found to play a crucial role for the successful and simultaneous predictions of a variety of water properties. This work not only aims at presenting an accurate model for water, but also at proposing strategies to develop classical accurate models for the predictions of structural, dynamic, and thermodynamic properties.
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Affiliation(s)
- Patrice Paricaud
- Department of Chemical Engineering, Vanderbilt University, Nashville, Tennesee 37235-1604, USA
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Abstract
Water is not restricted to moderate temperatures and low pressures, but can exist up to very high temperatures, far above its critical point at 647 K. In this supercritical regime, water can be gradually compressed from gas-like to liquid-like densities. The resulting dense supercritical states have extraordinary properties which can be tuned by temperature and pressure, and form the basis for innovative technologies. This Review covers the current knowledge of the major properties of supercritical water and its solutions with nonpolar, polar, and ionic compounds, and of the underlying molecular processes.
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Affiliation(s)
- Hermann Weingärtner
- Physikalische Chemie II, Ruhr-Universität Bochum, 44780 Bochum, Germany, Fax: (+49) 234-321-4293
| | - Ernst Ulrich Franck
- Institut für Physikalische Chemie, Universität Karlsruhe, 76128 Karlsruhe, Germany
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Striolo A, Gubbins KE, Chialvo AA, Cummings PT. Simulated water adsorption isotherms in carbon nanopores. Mol Phys 2004. [DOI: 10.1080/00268970410001668507] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Peltz C, Baranyai A, Chialvo AA, Cummings PT. Microstructure of Water At the Level of Three-particle Correlation Functions As Predicted by Classical Intermolecular Models. MOLECULAR SIMULATION 2003. [DOI: 10.1080/0892702031000065692] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Liu W, Wood RH, Doren DJ. Hydration free energy and potential of mean force for a model of the sodium chloride ion pair in supercritical water with ab initio solute–solvent interactions. J Chem Phys 2003. [DOI: 10.1063/1.1536164] [Citation(s) in RCA: 28] [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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Lı́sal M, Kolafa J, Nezbeda I. An examination of the five-site potential (TIP5P) for water. J Chem Phys 2002. [DOI: 10.1063/1.1514572] [Citation(s) in RCA: 86] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Arbuckle BW, Clancy P. Effects of the Ewald sum on the free energy of the extended simple point charge model for water. J Chem Phys 2002. [DOI: 10.1063/1.1451245] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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