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Elizondo-Aguilera LF, Cortés-Morales EC, Zubieta Rico PF, Medina-Noyola M, Castañeda-Priego R, Voigtmann T, Pérez-Ángel G. Arrested dynamics of the dipolar hard sphere model. SOFT MATTER 2020; 16:170-190. [PMID: 31774110 DOI: 10.1039/c9sm00687g] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
We report the combined results of molecular dynamics simulations and theoretical calculations concerning various dynamical arrest transitions in a model system representing a dipolar fluid, namely, N (soft core) rigid spheres interacting through a truncated dipole-dipole potential. By exploring different regimes of concentration and temperature, we find three distinct scenarios for the slowing down of the dynamics of the translational and orientational degrees of freedom: at low (η = 0.2) and intermediate (η = 0.4) volume fractions, both dynamics are strongly coupled and become simultaneously arrested upon cooling. At high concentrations (η≥ 0.6), the translational dynamics shows the features of an ordinary glass transition, either by compressing or cooling down the system, but with the orientations remaining ergodic, thus indicating the existence of partially arrested states. In this density regime, but at lower temperatures, the relaxation of the orientational dynamics also freezes. The physical scenario provided by the simulations is discussed and compared against results obtained with the self-consistent generalized Langevin equation theory, and both provide a consistent description of the dynamical arrest transitions in the system. Our results are summarized in an arrested states diagram which qualitatively organizes the simulation data and provides a generic picture of the glass transitions of a dipolar fluid.
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Affiliation(s)
- Luis F Elizondo-Aguilera
- Institut für Materialphysik im Weltraum, Deutsches Zentrum für Luft-und Raumfahrt (DLR), 51170 Köln, Germany.
| | - Ernesto C Cortés-Morales
- Instituto de Física, Universidad Autónoma de San Luis Potosí, Av. Manuel Nava 6, Zona Universitaria, 78290 San Luis Potosí, Mexico
| | - Pablo F Zubieta Rico
- Instituto de Física, Universidad Autónoma de San Luis Potosí, Av. Manuel Nava 6, Zona Universitaria, 78290 San Luis Potosí, Mexico
| | - Magdaleno Medina-Noyola
- Instituto de Física, Universidad Autónoma de San Luis Potosí, Av. Manuel Nava 6, Zona Universitaria, 78290 San Luis Potosí, Mexico
| | - Ramón Castañeda-Priego
- Departamento de Ingeniería Física, División de Ciencias e Ingenierías, Universidad de Guanajuato, Loma del Bosque 103, 37150 León, Mexico
| | - Thomas Voigtmann
- Institut für Materialphysik im Weltraum, Deutsches Zentrum für Luft-und Raumfahrt (DLR), 51170 Köln, Germany. and Department of Physics, Heinrich-Heine-Universität Düsseldorf, Universitätsstraße 1, 40225 Düsseldorf, Germany
| | - Gabriel Pérez-Ángel
- Departamento de Física Aplicada, CINVESTAV del IPN, A. P. 73 "Cordemex", 97310 Mérida, Yucatán, Mexico
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Satake A, Suzuki Y, Sugimoto M, Shimazaki T, Ishii H, Kuramochi Y. A Solvation/Desolvation Indicator Based on van der Waals Interactions between Solvents and Porphyrins. Chemistry 2018; 24:14733-14741. [PMID: 29989274 DOI: 10.1002/chem.201802402] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Revised: 06/26/2018] [Indexed: 12/16/2022]
Abstract
Solvation is a ubiquitous phenomenon associated with molecules in solutions. It often determines the equilibria of molecular systems and the rates of chemical reactions. Van der Waals interactions (a general term) includes weak interactions among noncharged compounds and it contributes significantly to solvation. The distinct observation of van der Waals interaction between solvent and porphyrin derivatives is reported herein. Bis(imidazolylporphyrinatozinc) structures connected through a 1,3-butadiyne moiety give two types of coordination polymers, E (extended) and S (stacked) polymers, exclusively. E polymers have larger solvent-accessible surface areas than the corresponding S polymers. Therefore, E polymers are better solvated than S polymers, providing an indicator of solvation and desolvation for the solvents used. A simple method (like a litmus test) was developed to evaluate the solvation ability of various solvents. Sixty-seven solvents and liquid compounds were tested, under the same conditions, using a conventional UV/Vis spectrometer. The results revealed a new liquid group with high solvation ability towards the porphyrins, and clarified van der Waals interaction assisted by secondary interaction on the substituents. The indicator system should contribute to the solution chemistry of molecules and materials, and to supramolecular chemistry interactions among hetero components.
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Affiliation(s)
- Akiharu Satake
- Graduate School of Science, Tokyo University of Science, 1-3 Kagurazaka, Shinjuku-ku, Tokyo, 162-8601, Japan.,Department of Chemistry, Faculty of Science Division II, Tokyo University of Science, Japan
| | - Yuki Suzuki
- Graduate School of Science, Tokyo University of Science, 1-3 Kagurazaka, Shinjuku-ku, Tokyo, 162-8601, Japan
| | - Motonobu Sugimoto
- Graduate School of Science, Tokyo University of Science, 1-3 Kagurazaka, Shinjuku-ku, Tokyo, 162-8601, Japan
| | - Tatsumi Shimazaki
- Graduate School of Science, Tokyo University of Science, 1-3 Kagurazaka, Shinjuku-ku, Tokyo, 162-8601, Japan
| | - Hidekazu Ishii
- Department of Chemistry, Faculty of Science Division II, Tokyo University of Science, Japan
| | - Yusuke Kuramochi
- Graduate School of Science, Tokyo University of Science, 1-3 Kagurazaka, Shinjuku-ku, Tokyo, 162-8601, Japan.,Department of Chemistry, Faculty of Science Division II, Tokyo University of Science, Japan
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Fuentes-Herrera M, Moreno-Razo JA, Guzmán O, López-Lemus J, Ibarra-Tandi B. Separating the effects of repulsive and attractive forces on the phase diagram, interfacial, and critical properties of simple fluids. J Chem Phys 2016; 144:214502. [PMID: 27276958 DOI: 10.1063/1.4953002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Molecular simulations in the canonical and isothermal-isobaric ensembles were performed to study the effect of varying the shape of the intermolecular potential on the phase diagram, critical, and interfacial properties of model fluids. The molecular interactions were modeled by the Approximate Non-Conformal (ANC) theory potentials. Unlike the Lennard-Jones or Morse potentials, the ANC interactions incorporate parameters (called softnesses) that modulate the steepness of the potential in their repulsive and attractive parts independently. This feature allowed us to separate unambiguously the role of each region of the potential on setting the thermophysical properties. In particular, we found positive linear correlation between all critical coordinates and the attractive and repulsive softness, except for the critical density and the attractive softness which are negatively correlated. Moreover, we found that the physical properties related to phase coexistence (such as span of the liquid phase between the critical and triple points, variations in the P-T vaporization curve, interface width, and surface tension) are more sensitive to changes in the attractive softness than to the repulsive one. Understanding the different roles of attractive and repulsive forces on phase coexistence may contribute to developing more accurate models of liquids and their mixtures.
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Affiliation(s)
- M Fuentes-Herrera
- Facultad de Ciencias, Universidad Autónoma del Estado de México, CP 50000, Toluca, Mexico
| | - J A Moreno-Razo
- Departamento de Física, Universidad Autónoma Metropolitana-Iztapalapa, CP 09340, Mexico D.F., Mexico
| | - O Guzmán
- Departamento de Física, Universidad Autónoma Metropolitana-Iztapalapa, CP 09340, Mexico D.F., Mexico
| | - J López-Lemus
- Facultad de Ciencias, Universidad Autónoma del Estado de México, CP 50000, Toluca, Mexico
| | - B Ibarra-Tandi
- Facultad de Ciencias, Universidad Autónoma del Estado de México, CP 50000, Toluca, Mexico
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