nth-Nearest neighbour distribution functions of a binary fluid mixture

Sur, Pradip Kumar; Bhattacharjee, Biplab

doi:10.1007/s12039-009-0110-z

Cited by 7 publications

(8 citation statements)

References 12 publications

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“…The nearest-neighbor approach has been already shown to give interesting results in analyzing the local structure of hard sphere systems, 57−59 supercooled liquids, 60,61 supercritical CO 2 , 53,55 and binary mixtures. 54,62 ■ COMPUTATIONAL DETAILS All of the MD simulations have been carried out using the GROMACS 4.5.5 simulation package. 63 Initial systems, containing 864 particles (molecules, ion pairs, and/or their combinations), have been generated by Packmol 64 by placing the particles randomly in a cubic simulation box with periodic boundary conditions (PBC).…”

Section: ■ Introductionmentioning

confidence: 99%

“…Indeed, the calculation of these two distances allows one to characterize the radial and angular characteristics of the interionic and ion–solvent interactions. Here, we use the nearest-neighbor approach to calculate these distances in an unambiguous way. − In this approach, the neighbors are sorted by their distance from a central atom as the first second, etc. neighbors.…”

Section: Introductionmentioning

confidence: 99%

“…Indeed, the statistical radial distribution of the nearest neighbor is contracted in its corresponding average value, which takes implicitly into account also the shape of this distribution. The nearest-neighbor approach has been already shown to give interesting results in analyzing the local structure of hard sphere systems, − supercooled liquids, , supercritical CO 2 , , and binary mixtures. , …”

Section: Introductionmentioning

confidence: 99%

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Distance Angle Descriptors of the Interionic and Ion–Solvent Interactions in Imidazolium-Based Ionic Liquid Mixtures with Aprotic Solvents: A Molecular Dynamics Simulation Study

et al. 2019

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The aim of this paper is to quantify the changes of the interionic and ion–solvent interactions in mixtures of imidazolium-based ionic liquids, having tetrafluoroborate (BmimBF4), hexafluorophosphate (BmimPF6), trifluoromethylsulfonate (BmimTFO), or bis(trifluoromethanesulfonyl)imide (BmimTFSI), anions, and polar aprotic molecular solvents, such as acetonitrile (AN), γ-butyrolactone (GBL), and propylene carbonate (PC). For this purpose, we calculate, using the nearest-neighbor approach, the average distance between the imidazolium ring H atom in positions 2, 4, and 5 (H2,4,5) and the nearest high-electronegativity atom of the solvent or anion (X) as distance descriptors, and the mean angle formed by the C2,4,5–H2,4,5 bond and the H2,4,5···X axis around the H2,4,5 atom as angular descriptors of the cation–anion and cation–solvent interactions around the ring C–H groups. The behavior of these descriptors as a function of the ionic liquid mole fraction is analyzed in detail. The obtained results show that the extent of the change of these descriptors with respect to their values in the neat ionic liquid depends both on the nature of the anion and on the mixture composition. Thus, in the case of the mixtures of the molecular solvents with BmimBF4 and BmimTFO, a small change of the distance and a drastic increase of the angular descriptor corresponding to the cation–anion interactions are observed with decreasing mole fraction of the ionic liquid, indicating that the anion moves from the above/below position (with respect to the imidazolium ring plane) to a position that is nearly linearly aligned with the C2–H2 bond and hinders the possible interaction between the C2–H2 group and the solvent molecules. On the other hand, in the case of mixtures of BmimTFSI and BmimPF6 with the molecular solvents, both the observed increase of the distance descriptor and the slight change of the angular descriptor with decreasing ionic liquid mole fraction are compatible with the direct interactions of the solvent with the C2–H2 group. The behavior of these descriptors is correlated with the experimentally observed 1H chemical shift of the C2–H2 group and the red shift of the C2–H2 vibrational mode, particularly at low ionic liquid mole fractions. The present results are thus of great help in interpreting these experimental observations.

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Section: ■ Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Distance Angle Descriptors of the Interionic and Ion–Solvent Interactions in Imidazolium-Based Ionic Liquid Mixtures with Aprotic Solvents: A Molecular Dynamics Simulation Study

et al. 2019

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“…supercooled liquids, 33,34 of supercritical CO 2 35,36 and of binary mixtures. 37,38 In this approach, the neighbors of a central atom are sorted by distance into the rst neighbors, second neighbors, etc. The nearest neighbor radial distribution functions, p a/b (r, n), can be dened then for each set of nearest neighbor atoms b (n is the order of the nearest neighbor) with respect to reference atoms a.…”

Section: B Analysis Of the Distance Threshold In Our Hybrid H-bond Cr...mentioning

confidence: 99%

The study of correlations between hydrogen bonding characteristics in liquid, sub- and supercritical methanol. Molecular dynamics simulations and Raman spectroscopy analysis

et al. 2013

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Molecular dynamics (MD) studies of hydrogen bonding (H-bonding) in liquid, sub- and supercritical methanol have been performed in a wide range of thermodynamic parameters of state, using various potential models and two H-bond criteria. It was shown that there is the universal correlation between the average number of H-bonds per molecule (n(HB)) and the mole fraction of H-bonded molecules (X(HB)) for the studied thermodynamic parameters of state. The same feature was observed for the correlations between fractions of molecules forming one (f1), two (f2), three (f3) H-bonds and X(HB). These correlations served to fit experimental Raman spectra of methanol recorded under sub- and supercritical conditions. The advantage of the approach used here is that f1, f2, f3 values have a clear physical meaning and are dependent on the values of state parameters.

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“…In order to rationalize the choice of these parameters, we propose to use the radial nearest neighbor distribution approach, which allows us to determine the two input parameters in a rational way. In this approach, ,− the neighbors of a central atom are sorted by distance into the first neighbors; second neighbors, etc. Separate radial distribution functions, p α–β ( n,r ) may be defined for each set of nearest neighbor atoms β (indicated by n ), and at distance r from the central atom α.…”

mentioning

confidence: 99%

On the Characterization of Inhomogeneity of the Density Distribution in Supercritical Fluids via Molecular Dynamics Simulation and Data Mining Analysis

et al. 2013

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We combined molecular dynamics simulation and DBSCAN algorithm (Density Based Spatial Clustering of Application with Noise) in order to characterize the local density inhomogeneity distribution in supercritical fluids. The DBSCAN is an algorithm that is capable of finding arbitrarily shaped density domains, where domains are defined as dense regions separated by low-density regions. The inhomogeneity of density domain distributions of Ar system in sub- and supercritical conditions along the 50 bar isobar is associated with the occurrence of a maximum in the fluctuation of number of particles of the density domains. This maximum coincides with the temperature, Tα, at which the thermal expansion occurs. Furthermore, using Voronoi polyhedral analysis, we characterized the structure of the density domains. The results show that with increasing temperature below Tα, the increase of the inhomogeneity is mainly associated with the density fluctuation of the border particles of the density domains, while with increasing temperature above Tα, the decrease of the inhomogeneity is associated with the core particles.

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nth-Nearest neighbour distribution functions of a binary fluid mixture

Cited by 7 publications

References 12 publications

Distance Angle Descriptors of the Interionic and Ion–Solvent Interactions in Imidazolium-Based Ionic Liquid Mixtures with Aprotic Solvents: A Molecular Dynamics Simulation Study

Distance Angle Descriptors of the Interionic and Ion–Solvent Interactions in Imidazolium-Based Ionic Liquid Mixtures with Aprotic Solvents: A Molecular Dynamics Simulation Study

The study of correlations between hydrogen bonding characteristics in liquid, sub- and supercritical methanol. Molecular dynamics simulations and Raman spectroscopy analysis

On the Characterization of Inhomogeneity of the Density Distribution in Supercritical Fluids via Molecular Dynamics Simulation and Data Mining Analysis

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