Vladimir A. Durov

Novel approaches to the structure and dynamics of liquids : experiments, theories and simulations

Preface. Intermolecular interactions and cooperative effects from electronic structure calculations: an effective means for developing interaction potentials for condensed phase simulations S.S. Xantheas. Models in theory of molecular liquid mixtures: structure, dynamics and physicochemical properties V.A. Durov. Classical versus quantum mechanical simulations: the accuracy of computer experiments in solution chemistry B.M. Rode, et al. Basic concepts and trends in ab initio molecular dynamics M.E. Tuckerman. Concepts of ionic solvation H. Krienke. Real time visualizing of atomic motions in dense phases S. Bratos, et al. Reverse Monte Carlo analyses of diffraction data on molecular liquids L. Pusztai. Structural change and nucleation characteristics of water/ice in confined geometry J. Dore, et al. Solvation structure of chloride and iodide atoms studied by means of EXAFS using a compact synchrotron radiation source K. Ozutsumi, H. Ohtaki. Ultrasonically induced birefringence in liquids and solutions H. Nomura, et al. Novel approaches in spectroscopy of interparticle interactions. Vibrational line profiles and anomalous non-coincidence effects S.A. Kirillov. Picosecond dynamic processes of molecular liquids in confined spaces. A review of results in porous glasses J. Yarwood. Photoinduced redox processes in phthalocyanine derivatives by resonance Raman spectroscopy and time resolved techniques H. Abramczyk, I. Szymczyk. Dielectric spectroscopy of solutions R. Buchner. Dynamics in intra-molecular polymer mixtures P. Holmqvist, G. Fytas. Visco-elastic behavior and small angle scattering of complex fluids H. Versmold, et al. Computer simulation studies of solvation dynamics in mixtures B.M. Ladanyi. Using simulations to study Vibrational relaxation of molecules in liquids R.M. Lynden-Bell, F.S. Zhang. Computational methods for analyzing the intermolecular resonant vibrational interactions in liquids and the noncoincidence effect of vibrational spectra H. Torii. Multipole-induced dipole contributions to the far-infrared spectra of diatomic molecules in non-polar solvents A. Medina, et al. Recent advances in the understanding of hydrophobic and hydrophilic effects: A theoretical and computer simulation perspective R.L. Mancera, et al. Molecular simulations of Nafion membranes in the presence of polar solvents D.A. Mologin, et al. Computer simulation of mesogens with ab initio interaction potentials: an application to oligophenyls I. Cacelli, et al. Phase transformations and orientational ordering in chemically disordered polymers - a modern primer L. Gutman, E. Shakhnovich. Conformational transitions in proteins and membranes J.C. Smith, et al. Structure, thermodynamics and critical properties of ionic fluids W. Schroer, H. Weingartner. Index.

Long range order and hydrogen bonding in liquid methanol: A Monte Carlo simulation

Abstract A Monte Carlo simulation of liquid methanol was performed in NVT ensemble at 298 K using a cubic simulation box containing 500 molecules. Long-range correlations in the liquid are discussed on the basis of site–site radial distribution functions. Hydrogen bonding and topological structure of the methanol aggregates were evaluated in detail, namely the number of linked molecules, formation of branches and cyclic structures. The necessity of larger simulation boxes for a full structural description and thermodynamic characterization of hydrogen-bonded liquids is clearly established by the results.

Models of liquid mixtures: Structure, dynamics, and properties

Models of the structure and properties of liquid mixtures are outlined. The main focus is on quasichemical models for the modeling of supramolecular ordering in mixtures, self-organized by H-bonds, leading to a unified description of their physicochemical properties. Models of polyvariable supramolecular species are discussed with respect to structure and composition of the mixtures, taking into account the cooperativity of H-bonding, and leading to a description of electric (dipole moment) and optic (polarizability) properties. We analyze the interrelations of thermodynamic functions (Gibbs energy, enthalpy, entropy), dielectric (permittivity) and optical properties (refractive index and its fluctuation derivatives, defining Rayleigh light scattering) of nonideal mixtures as well as the microscopic characteristics of the aggregates. Methods are developed in order to obtain both integral and differential parameters of aggregation. Models for the description of supramolecular reorganization, intramolecular transitions, and energy transfer during molecular thermal motion as well as fluctuation and relaxation phenomena are considered. Applications both to liquids and mixtures are outlined. The supramolecular assemblies in liquids with long-range molecular correlations are established. Macroscopic manifestations of the supramolecular organization in the properties of liquids are characterized.

Supramolecular structure and physicochemical properties of the mixture tetrachloromethane-methanol

Abstract The supramolecular structure and macroscopic properties over the whole concentration range and wide temperature interval of the mixture tetrachloromethane-methanol was studied. A structural model including the chainlike alcohol aggregates of various length and cyclic tetramers due to H-bonding OH…O as well as complexes of alcohol aggregates with a solvent molecule due to H-bonding OH…Cl was proved to describe thermodynamic excess functions (Gibbs energy, enthalpy), dielectric permittivity and Rayleigh light scattering ratios of the mixture tetrachloromethane-methanol. Thermodynamic (equilibrium constants, enthalpies and entropies of association processes) and structural parameters of the aggregates were obtained. Integral and differential parameters of aggregation in mixtures were evaluated. The long-range supramolecular ordering due to specific bonding was established. The unified analysis of the thermodynamic, dielectric and optic properties in terms of generalized quasichemical models was carried out. Supramolecular structure was found to play a significant role in determining the physicochemical properties of the mixture tetrachloromethane-methanol.

Modeling of supramolecular ordering in molecular liquids: Structure, physicochemical properties and macroscopic manifestations

Abstract The results of recent developments on modelling of supramolecular ordering and macroscopic properties of molecular liquids and mixtures are reviewed. The main attention is paid to the approach based on a generalized quasichemical association model for a set of thermodynamic, dielectric and optical properties of liquids and mixtures, selforganized by specific bonding. The hierarchy of theoretical models of molecular aggregates is considered. The nonideal mixture of molecular aggregates, polyvariant as regards structure and composition, is discussed. Interrelations between a set of the thermodynamic, dielectric, and optical properties of liquid systems, and the characteristics of quasichemical processes are presented. Some of the problems of a quasichemical approach for a thermodynamic description of internal processes in liquids have been outlined. Applications for thermodynamic functions of mixing, permittivity, coefficients of isotropic and anisotropic Rayleigh light scattering in molecular liquids and mixtures are considered. Aggregation in molecular liquids, including long range molecular correlations, is discussed in terms of the integral and differential parameters of aggregation. Macroscopic manifestations of supramolecular ordering in a set of the physicochemical properties of molecular liquids and mixtures are discussed. For the first time a unified approach for thermodynamic, dielectric and optical properties of molecular liquid systems, reflecting different molecular parameters, by this quasichemical method on the molecular-structural level has been realised.

Modeling of supramolecular ordering in mixtures: Structure, dynamics and properties

Abstract The results on modeling supramolecular ordering in molecular mixtures, selforganized by H-bonding and the unified description of their thermodynamic, dielectric, optic, and kinetic properties have been reviewed. The hierarchy of the models of supramolecular species mixtures in thermodynamics of non-ideal solutions has been analyzed. New models of polyvariable supramolecular species as regards structure and composition, taking into account the cooperativity on H-bonding, as well as the description of their structure, composition, electric (dipole moment) and optical (polarizability tensor) properties, are discussed. The interrelations between thermodynamic functions (Gibbs energy, enthalpy, entropy), dielectric (permittivity), optic (refractive index and its fluctuation derivatives, defining Rayleigh light scattering) and kinetic properties of mixtures and microscopic characteristics of supramolecular species are presented. The dynamic models for describing supramolecular reorganization, intermolecular transitions, and energy transfer during thermal molecular motion, as well as fluctuation and relaxation (acoustic, dielectric, optic) phenomena in liquids on the basis of thermodynamic models with internal variables of the different tensor dimension have been considered. Expressions for fluctuation and relaxation contributions for both equilibrium and kinetic properties of nonideal mixtures are obtained. Contributions to integral Rayleigh light scattering due to fluctuation of the scalar parameters have been established. The methods for obtaining both integral and differential parameters of aggregation have been developed. The applications as to individual liquids (alcohols, N-amides, etc.) as well to binary mixtures with directed attractional molecular forces like H-bonds and both negative (e.g. acetone-chloroform) and positive (e.g. hydrocarbon-alcohol, chloroform-alcohol, ketone-alcohol) deviations from ideal solution behaviour are presented. The data on the structure and thermodynamics (equilibrium constant, Gibbs energy, enthalpy, and entropy) of supramolecular aggregation due to H-bonding in liquids and mixtures were obtained. The supramolecular assemblies in molecular liquids, selforganized by H-bonding, consisting of tens Thus the different forms of supramolecular ordering, characterizing the multiformity of aggregates both to structure and composition, differently manifest the macroscopic properties of liquids and mixtures. Its clear from the data obtained, that in associated mixtures with their common parameters of the state there is formation of supramolecular aggregates, consisting of tens of molecules, due to attractional directed molecular interactions like H-bonding, here the distribution functions of the aggregates on the size are quite wide. This is the evidence on the long-range translational and orientational molecular correlations in mixtures containing labile supramolecular aggregates due to the selforganisation processes through H-bonding. These supramolecular aggregates of nanosizes play an important role in the physicochemical properties of liquid systems.

Molecular structure and physicochemical properties of acetone–chloroform mixtures

The molecular structure of acetone–chloroform mixtures has been studied. Thermodynamic mixing functions, permittivity, and Rayleigh ratios of isotropic and anisotropic light scattering are considered. A molecular model including the formation of the 1 : 1 and 1 : 2 molecular complexes is substantiated. A set of thermodynamic and structural parameters of the complex formation was obtained. The thermodynamic parameters of complex formation defined by the minimisation procedure for excess Gibbs energy of mixture was applied for calculation of excess enthalpy and entropy as well as dielectric and optical properties of mixtures. For the first time the unified representation and analysis of the thermodynamic, dielectric and optical properties of acetone–chloroform mixtures in terms of generalized quasichemical models on the molecular-structural level was realised.

Mixtures of halogenated hydrocarbons-organic solvent: molecular interactions, structure and physicochemical properties

Abstract The results on the modelling of molecular interactions, supramolecular organization and physicochemical properties of halogenated hydrocarbon mixtures with organic solvents are presented. The mixtures both with negative deviation from ideality, such as propanone–trichloromethane, dimethylsulfoxide (DMSO)–trichloromethane and positive one (tetrachloromethane–methanol, trichloromethane–methanol, trichloromethane–ethanol) has been studied. The models of the aggregation of mixtures investigated due to specific intermolecular interactions are proposed. The thermodynamic characteristics of aggregation (constants of equilibrium, Gibbs energy, enthalpy and entropy) and structural parameters of aggregates have been determined. The manifestations of the supramolecular ordering on the physicochemical properties of the mixture are discussed.

Modeling of Supramolecular Structure and Physicochemical Properties of the Propanone–Methanol Mixture

The results on modeling of the supramolecular organization and physicochemical properties of the propanone-methanol mixture are presented. An analysis of the excess thermodynamic functions (Gibbs energy, enthalpy, and entropy) and the permittivity of mixtures have been performed in the whole range of compositions and temperatures. It has been demonstrated that the model of supramolecular structure, taking into account the chain and cyclic association of methanol molecules and complexation of alcohol aggregates with propanone, describes the properties of the mixture. It established that both specific and universal interactions contribute to the positive deviations from the thermodynamic ideal solution behavior. Positive deviation of the dipole correlation factor from unity is due to a predominantly parallel orientation of the dipoles of the molecules in methanol aggregates and their complexes with propanone. The thermodynamic parameters of aggregation and structural parameters of aggregates have been determined. The cooperativity of H bonding was established. Distribution functions of the aggregate, according to size and structure, are presented. The manifestations of the supramolecular ordering on the physicochemical properties of the mixture are discussed.

Modeling of supramolecular structure and dielectric properties of butanols from melting point to supercritical state.

The supramolecular structure and dielectric properties of pure fluid butanols have been modeled in the temperature range from the melting point to the vicinity of the critical point using the quasichemical model of nonideal associated solution (QCNAS). The model of supramolecular structure takes into account both chain-like and cyclic aggregates. Dielectric permittivity and dipole correlation factor of n-, sec-, and tert-butanol are calculated in the temperature intervals 191-553, 166-533, and 298-503 K, respectively, using parameters obtained earlier for ambient conditions. The thermodynamic and structural parameters of supramolecular aggregation are reported. Size and structure distribution functions of aggregates are evaluated in the entire temperature range. Mean degree of aggregation of n-butanol decreases from hundreds at low temperatures to about 1.3 around critical point. The structure of n-butanol and s-butanol is characterized mainly by chain-like aggregation. tert-Butanols degree of aggregation is about 4 at ambient conditions and falls to 1.4 approaching the critical point. The fractions of molecules in chain-like and cyclic aggregates are comparable for tert-butanol. This conclusion refutes the frequently expressed opinion that tert-butanol consists mostly of cyclic species.