The Experts below are selected from a list of 23922 Experts worldwide ranked by ideXlab platform
James S. Johnson - One of the best experts on this subject based on the ideXlab platform.
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small angle neutron scattering from solutions of low equivalent weight organic salts in d2o
The Journal of Physical Chemistry, 1995Co-Authors: Patience C. Ho, R Triolo, James S. JohnsonAbstract:Small-angle neutron scattering from D{sub 2}O solutions of a series of organic salts, ranging from sodium toluenesulfonate to sodium triisopropylbenzenesulfonate, has been measured. Evidence of aggregation was found, at least at high concentrations, in all cases. The patterns were interpreted by the mean Spherical Approximation, and estimates of the size of the species are presented. Aggregate sizes increase with increase in equivalent weight. Addition of toluene increases aggregation number. A few measurements on solutions of sodium cyclohexylane carboxylates indicate that aggregates are somewhat smaller than those of aromatic salts of about the same number of carbons. 47 refs., 9 figs., 4 tabs.
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small angle neutron scattering from solutions of low equivalent weight organic salts in d2o
The Journal of Physical Chemistry, 1995Co-Authors: Patience C. Ho, R Triolo, James S. JohnsonAbstract:Small-angle neutron scattering from D{sub 2}O solutions of a series of organic salts, ranging from sodium toluenesulfonate to sodium triisopropylbenzenesulfonate, has been measured. Evidence of aggregation was found, at least at high concentrations, in all cases. The patterns were interpreted by the mean Spherical Approximation, and estimates of the size of the species are presented. Aggregate sizes increase with increase in equivalent weight. Addition of toluene increases aggregation number. A few measurements on solutions of sodium cyclohexylane carboxylates indicate that aggregates are somewhat smaller than those of aromatic salts of about the same number of carbons. 47 refs., 9 figs., 4 tabs.
Y C Chiew - One of the best experts on this subject based on the ideXlab platform.
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analytical integral equation theory for a restricted primitive model of polyelectrolytes and counterions within the mean Spherical Approximation ii radial distribution functions
Journal of Chemical Physics, 2003Co-Authors: N Von Solms, Y C ChiewAbstract:We have solved a polymerizing version of the mean Spherical Approximation for polyelectrolytes. The polyelectrolytes are modeled as tangentially-bonded hard-sphere segments interacting via the Coulombic potential in a continuous medium with dielectric constant. Analytical solutions for thermodynamic properties and radial distribution functions at contact, as well as numerical solutions using a multiple-variable version of the Perram algorithm for radial distribution functions at separations beyond the core, are obtained for some specific systems (negatively charged chains of various length and counterions). Comparisons were made with published experimental data for osmotic pressure and with computer simulations for radial distribution functions. Good agreement is found for the osmotic pressure at all ranges of density. Good agreement is found for the radial distribution functions at moderate to high density.
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restricted primitive model of dianions and counterions within the mean Spherical Approximation integral equation and thermodynamic perturbation theory
Journal of Chemical Physics, 2000Co-Authors: N Von Solms, Y C ChiewAbstract:We present an analytical integral equation theory for dimers modeled as hard-sphere tangentially connected anions and cationic hard-sphere monomeric counterions embedded in a continuum dielectric medium. Each hard-sphere segment on the dimer and hard-sphere counterion is univalent with unit diameters. The model was formulated in the context of the two-density Ornstein–Zernike integral equation theory within the mean Spherical Approximation. Analytical algebraic solutions for the model were obtained except for one parameter which requires simple numerical computation. The contact values of the radial distribution functions, internal energy, Helmholtz energy, and osmotic pressure of the system were derived analytically as a function of density and Bjerrum length via the energy route. Radial distribution functions beyond contact predicted by the theory were calculated numerically using the Perram algorithm. Thermodynamic perturbation theory was used to predict the osmotic pressure of longer chains using the ...
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analytical integral equation theory for a restricted primitive model of polyelectrolytes and counterions within the mean Spherical Approximation i thermodynamic properties
Journal of Chemical Physics, 1999Co-Authors: N Von Solms, Y C ChiewAbstract:We present an analytical integral equation theory for polyelectrolyte solutions modeled as linear freely-jointed tangent hard-sphere polyanionic chains and cationic hard-sphere monomeric counterions embedded in a continuum dielectric medium. Each hard-sphere segment on the polyelectrolyte chain and hard-sphere counterion are univalent with unit diameters. The model was formulated in the context of the multi density Ornstein–Zernike integral equation theory within the mean Spherical Approximation. Analytical solutions for the model were obtained using the ideal chain Approximation. The contact values of the radial distribution functions, internal energy, Helmholtz energy, osmotic pressure, and activity coefficient of the system were derived as a function of chain length, density, and Bjerrum length via the energy route. Predictions from the theory were compared with computer simulation data reported in the literature, and very good agreement was found.
N Von Solms - One of the best experts on this subject based on the ideXlab platform.
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analytical integral equation theory for a restricted primitive model of polyelectrolytes and counterions within the mean Spherical Approximation ii radial distribution functions
Journal of Chemical Physics, 2003Co-Authors: N Von Solms, Y C ChiewAbstract:We have solved a polymerizing version of the mean Spherical Approximation for polyelectrolytes. The polyelectrolytes are modeled as tangentially-bonded hard-sphere segments interacting via the Coulombic potential in a continuous medium with dielectric constant. Analytical solutions for thermodynamic properties and radial distribution functions at contact, as well as numerical solutions using a multiple-variable version of the Perram algorithm for radial distribution functions at separations beyond the core, are obtained for some specific systems (negatively charged chains of various length and counterions). Comparisons were made with published experimental data for osmotic pressure and with computer simulations for radial distribution functions. Good agreement is found for the osmotic pressure at all ranges of density. Good agreement is found for the radial distribution functions at moderate to high density.
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restricted primitive model of dianions and counterions within the mean Spherical Approximation integral equation and thermodynamic perturbation theory
Journal of Chemical Physics, 2000Co-Authors: N Von Solms, Y C ChiewAbstract:We present an analytical integral equation theory for dimers modeled as hard-sphere tangentially connected anions and cationic hard-sphere monomeric counterions embedded in a continuum dielectric medium. Each hard-sphere segment on the dimer and hard-sphere counterion is univalent with unit diameters. The model was formulated in the context of the two-density Ornstein–Zernike integral equation theory within the mean Spherical Approximation. Analytical algebraic solutions for the model were obtained except for one parameter which requires simple numerical computation. The contact values of the radial distribution functions, internal energy, Helmholtz energy, and osmotic pressure of the system were derived analytically as a function of density and Bjerrum length via the energy route. Radial distribution functions beyond contact predicted by the theory were calculated numerically using the Perram algorithm. Thermodynamic perturbation theory was used to predict the osmotic pressure of longer chains using the ...
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analytical integral equation theory for a restricted primitive model of polyelectrolytes and counterions within the mean Spherical Approximation i thermodynamic properties
Journal of Chemical Physics, 1999Co-Authors: N Von Solms, Y C ChiewAbstract:We present an analytical integral equation theory for polyelectrolyte solutions modeled as linear freely-jointed tangent hard-sphere polyanionic chains and cationic hard-sphere monomeric counterions embedded in a continuum dielectric medium. Each hard-sphere segment on the polyelectrolyte chain and hard-sphere counterion are univalent with unit diameters. The model was formulated in the context of the multi density Ornstein–Zernike integral equation theory within the mean Spherical Approximation. Analytical solutions for the model were obtained using the ideal chain Approximation. The contact values of the radial distribution functions, internal energy, Helmholtz energy, osmotic pressure, and activity coefficient of the system were derived as a function of chain length, density, and Bjerrum length via the energy route. Predictions from the theory were compared with computer simulation data reported in the literature, and very good agreement was found.
Patience C. Ho - One of the best experts on this subject based on the ideXlab platform.
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small angle neutron scattering from solutions of low equivalent weight organic salts in d2o
The Journal of Physical Chemistry, 1995Co-Authors: Patience C. Ho, R Triolo, James S. JohnsonAbstract:Small-angle neutron scattering from D{sub 2}O solutions of a series of organic salts, ranging from sodium toluenesulfonate to sodium triisopropylbenzenesulfonate, has been measured. Evidence of aggregation was found, at least at high concentrations, in all cases. The patterns were interpreted by the mean Spherical Approximation, and estimates of the size of the species are presented. Aggregate sizes increase with increase in equivalent weight. Addition of toluene increases aggregation number. A few measurements on solutions of sodium cyclohexylane carboxylates indicate that aggregates are somewhat smaller than those of aromatic salts of about the same number of carbons. 47 refs., 9 figs., 4 tabs.
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small angle neutron scattering from solutions of low equivalent weight organic salts in d2o
The Journal of Physical Chemistry, 1995Co-Authors: Patience C. Ho, R Triolo, James S. JohnsonAbstract:Small-angle neutron scattering from D{sub 2}O solutions of a series of organic salts, ranging from sodium toluenesulfonate to sodium triisopropylbenzenesulfonate, has been measured. Evidence of aggregation was found, at least at high concentrations, in all cases. The patterns were interpreted by the mean Spherical Approximation, and estimates of the size of the species are presented. Aggregate sizes increase with increase in equivalent weight. Addition of toluene increases aggregation number. A few measurements on solutions of sodium cyclohexylane carboxylates indicate that aggregates are somewhat smaller than those of aromatic salts of about the same number of carbons. 47 refs., 9 figs., 4 tabs.
Pierre Turq - One of the best experts on this subject based on the ideXlab platform.
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experimental and molecular dynamics studies of dysprosium iii salt solutions for a better representation of the microscopic features used within the binding mean Spherical Approximation theory
Journal of Physical Chemistry A, 2006Co-Authors: Alexandre Ruas, Pierre Turq, Jean-pierre Simonin, Philippe Guilbaud, Christophe Den Auwer, Christophe Cartier Dit Moulin, Philippe MoisyAbstract:This work is aimed at a predictive description of the thermodynamic properties of actinide(III) salt solutions at high concentration and 25 °C. A new solution of the binding mean Spherical Approximation (BIMSA) theory, based on the Wertheim formalism, for taking into account 1:1 and also 1:2 complex formation, is used to reproduce, from a simple procedure, experimental osmotic coefficient variation with concentration for three binary salt solutions of the same lanthanide(III) cation: dysprosium(III) perchlorate, nitrate, and chloride. The relevance of the fitted parameters is discussed, and their values are compared with available literature values. UV−vis/near-IR, time-resolved laser-induced fluorescence spectroscopy experiments, and molecular dynamics (MD) calculations were conducted for dilute to concentrated solutions (ca. 3 mol·kg-1) for a study of the microscopic behavior of DyCl3 binary solutions. Coupling MD calculations and extended X-ray absorption fine structure led to the determination of rel...
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uranyl vi nitrate salts modeling thermodynamic properties using the binding mean Spherical Approximation theory and determination of fictive binary data
Journal of Physical Chemistry B, 2006Co-Authors: Alexandre Ruas, Pierre Turq, Lesser Blum, Jean-pierre Simonin, Olivier Bernard, Barbara Caniffi, Philippe MoisyAbstract:This work is aimed at a description of the thermodynamic properties of highly concentrated aqueous solutions of uranyl nitrate at 25 °C. A new resolution of the binding mean Spherical Approximation (BIMSA) theory, taking into account 1-1 and also 1-2 complex formation, is developed and used to reproduce, from a simple procedure, experimental uranyl nitrate osmotic coefficient variation with concentration. For better consistency of the theory, binary uranyl perchlorate and chloride osmotic coefficients are also calculated. Comparison of calculated and experimental values is made. The possibility of regarding the ternary system UO2(NO3)2/ HNO3/H2O as a “simple” solution (in the sense of Zdanovskii, Stokes, and Robinson) is examined from water activity and density measurements. Also, an analysis of existing uranyl nitrate binary data is proposed and compared with our obtained data. On the basis of the concept of “simple” solution, values for density and water activity for the binary system UO2(NO3)2/H2O are proposed in a concentration range on which uranyl nitrate precipitates from measurements on concentrated solutions of the ternary system UO 2(NO3)2/ HNO3/H2O. This new set of binary data is “fictive” in the sense that the real binary system is not stable chemically. Finally, a new, interesting predictive capability of the BIMSA theory is shown.
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Experimental determination of water activity for binary aqueous cerium(III) ionic solutions: application to an assessment of the predictive capability of the binding mean Spherical Approximation model.
The journal of physical chemistry. B, 2005Co-Authors: Alexandre Ruas, Pierre Turq, Jean-pierre Simonin, Philippe MoisyAbstract:This work is aimed at a description of the thermodynamic properties of actinide salt solutions at high concentration. The predictive capability of the binding mean Spherical Approximation (BIMSA) theory to describe the thermodynamic properties of electrolytes is assessed in the case of aqueous solutions of lanthanide(III) nitrate and chloride salts. Osmotic coefficients of cerium(III) nitrate and chloride were calculated from other lanthanide(III) salts properties. In parallel, concentrated binary solutions of cerium nitrate were prepared in order to measure experimentally its water activity and density as a function of concentration, at 25 °C. Water activities of several binary solutions of cerium chloride were also measured to check existing data on this salt. Then, the properties of cerium chloride and cerium nitrate solutions were compared within the BIMSA model. Osmotic coefficient values for promethium nitrate and promethium chloride given by this theory are proposed. Finally, water activity measure...
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transport coefficients of aqueous dodecyltrimethylammonium bromide solutions comparison between experiments analytical calculations and numerical simulations
Journal of Chemical Physics, 2004Co-Authors: Marie Jardat, Serge Durandvidal, N Mota, Pierre TurqAbstract:We study dynamical properties of ionic species in aqueous solutions of dodecyltrimethylammonium bromide, for several concentrations below and above the critical micellar concentration (cmc). New experimental determinations of the electrical conductivity are given which are compared to results obtained from an analytical transport theory; transport coefficients of ions in these solutions above the cmc are also computed from Brownian dynamics simulations. Analytical calculations as well as the simulation treat the solution within the framework of the continuous solvent model. Above the cmc, three ionic species are considered: the monomer surfactant, the micelle and the counterion. The analytical transport theory describes the structural properties of the electrolyte solution within the mean Spherical Approximation and assumes that the dominant forces which determine the deviations of transport processes from the ideal behavior (i.e., without any interactions between ions) are hydrodynamic interactions and e...
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transport equations for concentrated electrolyte solutions reference frame mutual diffusion
Journal of Chemical Physics, 2002Co-Authors: Jeanfrancois Dufreche, Olivier Bernard, Pierre TurqAbstract:Transport coefficients of dissociated electrolytes in aqueous solution are studied in the framework of the primitive model of ionic solutions in which the solvent is a dielectric continuum. Simple explicit expressions are obtained by using a combination of Smoluchowski equation for the dynamics and the mean Spherical Approximation (MSA) for the equilibrium pair correlation function. The case of symmetrical and dissymmetrical electrolytes is examined. In the case of the mutual diffusion, a reference-frame correction, that can be obtained from density measurements has to be taken into account for molar concentrations. The combined Smoluchowski/MSA theory of the primitive model is found to be self-consistent since it is able to describe simultaneously the different transport and equilibrium properties up to high concentrations (1–2 mol l−1).
