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Ramos F, Ramos A, Pellicane G, Lee LL. Construction of a composite-sphere model for molecules of tetrahedral symmetry. Mol Phys 2021. [DOI: 10.1080/00268976.2021.1913254] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Affiliation(s)
- Franklin Ramos
- Department of Chemical & Materials Engineering, California State University, Pomona, CA, USA
| | - Ana Ramos
- Department of Chemical & Materials Engineering, California State University, Pomona, CA, USA
| | - Giuseppe Pellicane
- Dipartimento di Scienze Biomediche, Odontoiatriche e delle Immagini Morfologiche e Funzionali Università degli Studi di Messina, Messina, Italy
- CNR-IPCF, Messina, Italy
- School of Chemistry and Physics, University of Kwazulu-Natal, Pietermaritzburg, South Africa
- National Institute of Theoretical Physics (NIThEP), Pietermaritzburg, South Africa
| | - Lloyd L. Lee
- Department of Chemical & Materials Engineering, California State University, Pomona, CA, USA
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Pal D, Agrawal SK, Chakraborty A, Chakraborty S. Competition between the hydrogen bond and the halogen bond in a [CH 3OH-CCl 4] complex: a matrix isolation IR spectroscopy and computational study. Phys Chem Chem Phys 2020; 22:22465-22476. [PMID: 32996938 DOI: 10.1039/d0cp03855e] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Methanol (CH3OH) is the simplest alcohol and carbon tetrachloride (CCl4) is widely used as a solvent in the chemical industry. CH3OH and CCl4 are both important volatile substances in the atmosphere and CCl4 is an important precursor for atmospheric ozone depletion. Moreover, mixtures of CH3OH and CCl4 are an important class of non-aqueous mixtures as they exhibit a large deviation from Raoult's law. The specific interaction between CH3OH and CCl4 is not yet investigated experimentally. The interaction between CH3OH and CCl4 at the molecular level can be twofold: hydrogen bond (O-HCl) and halogen bond (C-ClO) interaction. One halogen bonded minimum and two hydrogen bonded minima are identified in the dimer potential energy surface. Herein, the 1 : 1 complex of [CH3OH-CCl4] has been characterised using matrix-isolation infrared spectroscopy and electronic structure calculations to investigate the competition between hydrogen bonded and halogen bonded complexes. Vibrational spectra have been monitored in the C-Cl, C-O, and O-H stretching regions. The exclusive formation of halogen bonded 1 : 1 complexes in argon and nitrogen matrices is confirmed by a combination of experimental and simulated vibrational frequency, stabilisation energy, energy decomposition analysis, and natural bond orbital and atoms-in-molecules analyses. This investigation helps to understand the specific interactions in the [CH3OH-CCl4] mixture and also the possibilities of formation of halogen bonded atmospheric complexes that may influence the atmospheric chemical activities, and enhance aerosol formation and deposition of CCl4.
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Affiliation(s)
- Dhritabrata Pal
- Department of Chemistry, Birla Institute of Technology and Science, Vidya Vihar, Pilani, Rajasthan - 333031, India.
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Moinuddin M, Biswas P, Tripathy M. The effect of surface roughness on the phase behavior of colloidal particles. J Chem Phys 2020; 152:044902. [PMID: 32007055 DOI: 10.1063/1.5136080] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Shape anisotropy of colloidal particles can give rise to complex intermolecular interactions that determine particle packing and phase behavior. The vapor-liquid coexistence curves of attractive rough particles display a shift when compared to attractive smooth spherical particles. We use Integral Equation Theory (IET) to determine the vapor-liquid spinodal phase diagram of smooth and rough colloidal particles interacting through square-well attraction. Additionally, we use Gibbs Ensemble Monte Carlo (GEMC) simulations to locate their vapor-liquid coexistence curves. We model a rough colloidal particle as a spherical core with small beads embedded on its surface. The critical point of smooth spherical particle systems predicted by theory and simulations is in quantitative agreement. An increase in surface roughness due to an increase in either the number of beads or the diameter of the beads has a modest effect on the local structure of the system in the supercritical region. In contrast, increasing surface roughness consistently shifts the vapor-liquid coexistence curves to higher temperatures. The critical temperature is found to be a quadratic function of the number of beads. At a fixed bead size and number of beads, the critical temperature does not vary with the arrangement of beads on the core. Both IET and GEMC simulations predict that unlike critical temperatures, critical packing fractions vary non-monotonically with surface roughness. We find that the feasibility and accuracy of the integral equation theory depend sensitively on the chosen closure combination.
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Affiliation(s)
- Md Moinuddin
- Department of Chemical Engineering, Indian Institute of Technology Bombay, Mumbai 400076, Maharashtra, India
| | - Prithwish Biswas
- Department of Chemical Engineering, Indian Institute of Technology Bombay, Mumbai 400076, Maharashtra, India
| | - Mukta Tripathy
- Department of Chemical Engineering, Indian Institute of Technology Bombay, Mumbai 400076, Maharashtra, India
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Munaò G, Saija F. Evidence of Structural Inhomogeneities in Hard-Soft Dimeric Particles without Attractive Interactions. MATERIALS 2019; 13:ma13010084. [PMID: 31877947 PMCID: PMC6981562 DOI: 10.3390/ma13010084] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Revised: 12/16/2019] [Accepted: 12/17/2019] [Indexed: 11/16/2022]
Abstract
We perform Monte Carlo simulations of a simple hard-soft dimeric model constituted by two tangent spheres experiencing different interactions. Specifically, two hard spheres belonging to different dimers interact via a bare hard-core repulsion, whereas two soft spheres experience a softly repulsive Hertzian interaction. The cross correlations are soft as well. By exploring a wide range of temperatures and densities we investigate the capability of this model to document the existence of structural inhomogeneities indicating the possible onset of aggregates, even if no attraction is set. The fluid phase behavior is studied by analyzing structural and thermodynamical properties of the observed structures, in particular by computing radial distribution functions, structure factors and cluster size distributions. The numerical results are supported by integral equation theories of molecular liquids which allow for a finer and faster spanning of the temperature-density diagram. Our results may serve as a framework for a more systematic investigation of self-assembled structures of functionalized hard-soft dimers able to aggregate in a variety of structures widely oberved in colloidal dispersion.
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Affiliation(s)
- Gianmarco Munaò
- Dipartimento di Scienze Matematiche e Informatiche, Scienze Fisiche e Scienze della Terra, Università degli Studi di Messina, Viale F. Stagno d’Alcontres 31, 98166 Messina, Italy
- Correspondence: (G.M.); (F.S.)
| | - Franz Saija
- CNR-IPCF, Viale F. Stagno d’Alcontres 37, 98158 Messina, Italy
- Correspondence: (G.M.); (F.S.)
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Lovrinčević B, Bella A, Le Tenoux-Rachidi I, Požar M, Sokolić F, Perera A. Methanol-ethanol “ideal” mixtures as a test ground for the computation of Kirkwood-Buff integrals. J Mol Liq 2019. [DOI: 10.1016/j.molliq.2019.111447] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Baptista A, Perera A. Modeling micro-heterogeneity in mixtures: The role of many body correlations. J Chem Phys 2019; 150:064504. [PMID: 30770003 DOI: 10.1063/1.5066598] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
A two-component interaction model is introduced herein, which allows us to describe macroscopic miscibility with various modes of tunable micro-segregation, ranging from phase separation to micro-segregation, and is in excellent agreement with structural quantities obtained from simulations and the liquid state hypernetted-chain like integral equation theory. The model is based on the conjecture that the many-body correlation bridge function term in the closure relation can be divided into one part representing the segregation effects, which are modeled herein, and the usual part representing random many body fluctuations. Furthermore, the model allows us to fully neglect these second contributions, thus increasing the agreement between the simulations and the theory. The analysis of the retained part of the many body correlations gives important clues about how to model the many body bridge functions for more realistic systems exhibiting micro-segregation, such as aqueous mixtures.
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Affiliation(s)
- Anthony Baptista
- Laboratoire de Physique Théorique de la Matière Condensée (UMR CNRS 7600), Sorbonne Université, 4 Place Jussieu, F75252 Paris Cedex 05, France
| | - Aurélien Perera
- Laboratoire de Physique Théorique de la Matière Condensée (UMR CNRS 7600), Sorbonne Université, 4 Place Jussieu, F75252 Paris Cedex 05, France
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Munaò G, Costa D, Caccamo C. Development of molecular closures for the reference interaction site model theory with application to square-well and Lennard-Jones homonuclear diatomics. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2016; 28:414007. [PMID: 27548461 DOI: 10.1088/0953-8984/28/41/414007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Inspired by significant improvements obtained for the performances of the polymer reference interaction site model (PRISM) theory of the fluid phase when coupled with 'molecular closures' (Schweizer and Yethiraj 1993 J. Chem. Phys. 98 9053), we exploit a matrix generalization of this concept, suitable for the more general RISM framework. We report a preliminary test of the formalism, as applied to prototype square-well homonuclear diatomics. As for the structure, comparison with Monte Carlo shows that molecular closures are slightly more predictive than their 'atomic' counterparts, and thermodynamic properties are equally accurate. We also devise an application of molecular closures to models interacting via continuous, soft-core potentials, by using well established prescriptions in liquid state perturbation theories. In the case of Lennard-Jones dimers, our scheme definitely improves over the atomic one, providing semi-quantitative structural results, and quite good estimates of internal energy, pressure and phase coexistence. Our finding paves the way to a systematic employment of molecular closures within the RISM framework to be applied to more complex systems, such as molecules constituted by several non-equivalent interaction sites.
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Affiliation(s)
- Gianmarco Munaò
- Dipartimento di Scienze Matematiche e Informatiche, Scienze Fisiche e Scienze della Terra, Università degli Studi di Messina, Viale F. Stagno d'Alcontres 31, 98166 Messina, Italy
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Munaò G, Urbic T. Structure and thermodynamics of core-softened models for alcohols. J Chem Phys 2015; 142:214508. [DOI: 10.1063/1.4922164] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Gianmarco Munaò
- Dipartimento di Fisica e di Scienze della Terra, Università degli Studi di Messina, Viale F. Stagno d’Alcontres 31, 98166 Messina, Italy
| | - Tomaz Urbic
- Department of Chemistry and Chemical Technology, Chair of Physical Chemistry, University of Ljubljana, Večna pot 113, SI-1000 Ljubljana, Slovenia
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Šoltésová M, Benda L, Peksa M, Czernek J, Lang J. Determination of size of molecular clusters of ethanol by means of NMR diffusometry and hydrodynamic calculations. J Phys Chem B 2014; 118:6864-74. [PMID: 24853047 DOI: 10.1021/jp501648x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The microscopic structure of ethanol in the liquid state is characterized as a dynamic equilibrium of hydrogen-bonded clusters of different sizes and topologies. We have developed a novel method for determination of the average size of the clusters that combines the measurement of diffusion coefficient by means of NMR diffusometry technique and hydrodynamic simulations. The approach includes the use of HydroNMR [J. Garcı̀a de la Torre, M. L. Huertas, and B. Carrasco, J. Magn. Reson. 147, 2000, 138] for small molecules, which is attained here by the calibration procedure using a dilute solution of tetramethylsilane. It is thus possible to correlate the experimentally determined diffusion coefficient of ethanol with calculated diffusion coefficients of the modeled clusters of different sizes. We found that average size of the clusters in 0.16 M solution of ethanol in n-hexane corresponds to the monomer above 300 K and to the pentamer/hexamer below 240 K. The clusters in the case of 0.44 M solution are generally slightly larger, from the average size corresponding to the dimer at 320 K and the hexamer at 210 K.
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Affiliation(s)
- Mária Šoltésová
- Department of Low Temperature Physics, Faculty of Mathematics and Physics, Charles University in Prague , V Holešovičkách 2, CZ-18000 Prague 8, Czech Republic
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Gómez-Álvarez P, Romaní L, González-Salgado D. Association effects in the {methanol + inert solvent} system via Monte Carlo simulations. I. Structure. J Chem Phys 2013; 138:204505. [PMID: 23742491 DOI: 10.1063/1.4807309] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
In this work, the clusters residing in the {methanol + inert solvent} binary system have been characterized using a specific methodology in the framework of Monte Carlo molecular simulations. The cluster classification scheme considered distinguishes into five types: linear chains, cyclic clusters or isolated rings, branched linear chains, branched cyclic clusters, and composite rings. The procedure allows one to compute the next rich structural information: the fraction of molecules in the monomer or associated state, the fraction of each type of aggregate with a given size (and of molecules belonging to them), and the most probable and average cluster size for each type; likewise, the degree of branching in branched linear chains and the size distribution of the inner ring in branched cyclic clusters can be quantified. Specifically, all these properties were obtained for the {Optimized Potential for Liquid Simulation methanol + Lennard-Jones spheres} system at 298.15 K and 1 bar throughout the composition range. The results have provided a complete structural picture of this mixture describing comprehensively the effect of dilution into the hydrogen-bonded network of the pure associated fluid.
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Affiliation(s)
- Paula Gómez-Álvarez
- Department of Applied Physics, University of Vigo, As Lagoas s∕n, 32004 Ourense, Spain
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Kežić B, Perera A. Towards a more accurate reference interaction site model integral equation theory for molecular liquids. J Chem Phys 2011; 135:234104. [DOI: 10.1063/1.3666006] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Munaó G, Costa D, Sciortino F, Caccamo C. Simulation and theory of a model for tetrahedral colloidal particles. J Chem Phys 2011; 134:194502. [DOI: 10.1063/1.3582904] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
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