Self-association of urea in aqueous solutions: A Voronoi polyhedron analysis study

Idriss, Hicham; Damay, P.; Kitamura, Yuichi; Jedlovszky, Pál

doi:10.1063/1.2996348

Cited by 42 publications

(63 citation statements)

References 57 publications

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“…51 Hence, in case of self-association of the components in binary mixtures, i.e., when both individual components show inhomogeneous density distribution, the P(V) distribution obtained by disregarding on of the two components exhibits the exponentially decaying tail (as in this case the self-associates of the disregarded component are transformed to empty regions in the system). 49 On the other hand, in the lack of such selfassociation the VP volume distribution remains of Gaussian shape even when one of the two components is disregarded in the analysis. Figure 5 shows the P(V) distributions obtained both by taking both components into account and by disregarding one of them.…”

Section: Volume Distribution the Volume Distributions Of The Voronoimentioning

confidence: 99%

The local environment of the molecules in water–DMSO mixtures, as seen from computer simulations and Voronoi polyhedra analysis

Idriss

Marekha

Киселев

et al. 2015

Phys. Chem. Chem. Phys.

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Running title: Voronoi analysis of water-DMSO mixtures * Electronic mail: nacer.idrissi@univ-lille1.fr (A.I), pali@chem.elte.hu (P. J.) 2 Graphical and textual abstract for the contents page:The local structure of DMSO-water mixtures is studied by computer simulation and Voronoi analysis 3 AbstractMolecular dynamics simulations of water- DMSO mixtures, containing 10,20,30,40,50, 60, 70, 80, and 90 mol% DMSO, respectively, have been performed on the isothermalisobaric (N,p,T) ensemble at T = 298 K and at the pressure equal to the experimental vapor pressure at each mixture composition. In addition, simulations of the two neat systems have also been performed for reference. The potential models used in the simulations are known to excellently reproduce the mixing properties of these compounds. The simulation results have been analyzed in detail by means of the Voronoi polyhedra (VP) of the molecules.Distributions of the VP volume and asphericity parameter as well as that of the radius of the spherical intermolecular voids have been calculated. Detailed analyses of these distributions have revealed that both molecules prefer to be in an environment consisting of both types of molecules, but the affinity of DMSO for mixing with water is clearly stronger than that of water for mixing with DMSO. As a consequence, the dilution of the two neat liquids by the other component has been found to follow different mechanisms: when DMSO is added to neat water small domains of neat-like water persist up to the equimolar composition, whereas no such domains are found when neat DMSO is diluted by water. The observed behavior is also in line with the fact that the main thermodynamic driving force behind the full miscibility of water and DMSO is the energy change accompanying their mixing, and that the entropy change accompanying this mixing is negative in systems of low, and positive in systems of high DMSO mole fractions. Finally, we have found a direct evidence for the existence of strong hydrogen bonded complexes formed by one DMSO and two water molecules, but it has also been shown that these complexes are in equilibrium with single (monomeric) water and DMSO molecules in the mixed systems.4

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Section: Volume Distribution the Volume Distributions Of The Voronoimentioning

confidence: 99%

The local environment of the molecules in water–DMSO mixtures, as seen from computer simulations and Voronoi polyhedra analysis

Idriss

Marekha

Киселев

et al. 2015

Phys. Chem. Chem. Phys.

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“…Further, a new method has recently been developed for detecting and characterizing such self-aggregates by means of the Voronoi analysis. [59] In a two-dimensional assembly of seeds, the Voronoi polygon (VP) of a given seed is the locus of points that are closer to this seed than to any other. [60] Therefore, the VPs of a (planar) system fill the plane without gaps and overlaps.…”

Section: Surface Aggregationmentioning

confidence: 99%

Molecular Dynamics Simulation of the Adsorption of Oxalic Acid on an Ice Surface

2010

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The adsorption properties of oxalic acid molecules on the surface of hexagonal ice are investigated by means of molecular dynamics simulations performed at tropospheric temperatures. Although the oxalic acid-water interaction is strong at low coverage, due to the possible formation of a large number of hydrogen bonds between the adsorbed oxalic acid and the surface water molecules, the results of the simulations at finite coverage show the predominant role played by the oxalic acid-oxalic acid lateral interactions in the adsorption/desorption process. These interactions are even stronger than the water-water or water-oxalic acid interactions. With increasing temperature these strong lateral interactions favor the formation of oxalic acid aggregates on the ice surface, with the concomitant departure of water molecules through the ducts in the adsorbed layer created by the aggregation process. These results support conclusions of experimental data on the oxalic acid-ice interactions. Moreover, in comparison to previously obtained results for formic and acetic acid adsorbed on ice, the present study suggests that not only the organic functionality is of importance for atmospheric implications of partially oxidized hydrocarbons (POH) interactions with ice, but also the balance between water-ice, water-POH, and POH-POH interactions.

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“…74 Therefore, in binary systems where the like components form self-associates, the VP are distribution obtained by disregarding the molecules of one of the two components, and taking only those of the other one into account, also exhibits the exponentially decaying tail at large area values (as the areas occupied by the self-associates of the disregarded component are converted to empty areas this way). 75 To characterize the extent of self-association of the like molecules at the surface of acetone-water mixtures we have projected the center (i.e., carboxylic C and O atom for acetone and water, respectively) of each surface molecule to the macroscopic plane of the liquid surface, YZ, and performed VP analysis on these projections. The distributions of the VP area, A, have been determined in three different ways, i.e., taking both types of molecules into account, taking only acetone molecules into account while disregarding the water molecules, and taking only water molecules into account while disregarding the acetone molecules.…”

Section: Itim Analysesmentioning

confidence: 99%

Properties of the Liquid–Vapor Interface of Acetone–Water Mixtures. A Computer Simulation and ITIM Analysis Study

et al. 2015

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Self-association of urea in aqueous solutions: A Voronoi polyhedron analysis study

Cited by 42 publications

References 57 publications

The local environment of the molecules in water–DMSO mixtures, as seen from computer simulations and Voronoi polyhedra analysis

The local environment of the molecules in water–DMSO mixtures, as seen from computer simulations and Voronoi polyhedra analysis

Molecular Dynamics Simulation of the Adsorption of Oxalic Acid on an Ice Surface

Properties of the Liquid–Vapor Interface of Acetone–Water Mixtures. A Computer Simulation and ITIM Analysis Study

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