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Požar M, Lovrinčević B, Perera A. The influence of charge ordering in the microscopic structure of monohydroxy alcohols. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2024; 36:265102. [PMID: 38537282 DOI: 10.1088/1361-648x/ad3870] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2023] [Accepted: 03/27/2024] [Indexed: 04/06/2024]
Abstract
While radiation scattering data provides insight inside the microstructure of liquids, the Debye relation relating the scattering intensityI(k) to the atom-atom structure factorsSab(k)shows that, ultimately, it is these individual structure correlation functions which contain the relevant information about the micro-structure. However, these quantities are not observables, except in few cases where one can invert the Debye relation to obtain the structure functions. In the majority of other cases, the need for model dependent computer simulations is unavoidable. The resulting calculations reveal that the scattering pre-peak is the result of cancellations between positive pre-peaks and negative anti-peaks contributions from the atom-atom structure factors. What of systems where this cancellation is such that it entirely suppresses the scattering pre-peak? One would be tempted to falsely conclude that there is no underlying micro-heterogeneity. Hence, the structure functions appear as hidden variables, and it is important to understand the relation between their features and the micro-structure of the system. Through the computer simulation study of various mono-ols, ranging from methanol to 1-nonanol, as well as the branched octanols, we show how the features of the atom-atom pair correlation functiongab(r)affect that of the structure factorsSab(k), and reveal that the micro-structure is ultimately the result of the charge ordering between different atoms in the system.
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Affiliation(s)
- Martina Požar
- Department of Physics, Faculty of Science, University of Split, Rudjera Boškovića 33, 21000 Split, Croatia
| | - Bernarda Lovrinčević
- Department of Physics, Faculty of Science, University of Split, Rudjera Boškovića 33, 21000 Split, Croatia
| | - Aurélien Perera
- Department of Physics, Faculty of Science, University of Split, Rudjera Boškovića 33, 21000 Split, Croatia
- 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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Lovrinčević B, Požar M, Jukić I, Perera A. Role of Charge Ordering in the Dynamics of Cluster Formation in Associated Liquids. J Phys Chem B 2023. [PMID: 37336720 DOI: 10.1021/acs.jpcb.3c01077] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/21/2023]
Abstract
Liquids are archetypes of disordered systems, yet liquids of polar molecules are locally more ordered than nonpolar molecules, due to the Coulomb interaction based charge ordering phenomenon. Hydrogen bonded liquids, such as water or alcohols, for example, represent a special type of polar liquids, in that they form labile clustered local structures. For water, in particular, hydrogen bonding and the related local tetrahedrality, play an important role in the various attempts to understand this liquid. However, labile structures imply dynamics, and it is not clear how it affects the understanding of this type of liquids from purely static point of view. Herein, we propose to reconsider hydrogen bonding as a charge ordering process. This concept allows us to demonstrate the insufficiency of the analysis of the microscopic structure based solely on static pair correlation functions, and the need for dynamical correlation functions, both in real and reciprocal space. The subsequent analysis allows to recover several aspects of our understanding of hydrogen bonded liquids, but from the charge order perspective. For water, it confirms the jump rotation picture found recently, and it allows to rationalize the contradicting pictures that arise when following the interpretations based on hydrogen bonding. For alcohols, it allows to understand the dynamical origin of the scattering prepeak, which does not exist for water, despite the fact that both these liquids have very similar hydroxyl group chain clusters. The concept of charge ordering complemented by the analysis of dynamical correlation functions appear as a promising way to understand microheterogeneity in complex liquids and mixtures from kinetics point of view.
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Affiliation(s)
- Bernarda Lovrinčević
- Faculty of Science, University of Split, Rudjera Boškovića 33, 21000 Split, Croatia
| | - Martina Požar
- Faculty of Science, University of Split, Rudjera Boškovića 33, 21000 Split, Croatia
| | - Ivo Jukić
- Faculty of Science, University of Split, Rudjera Boškovića 33, 21000 Split, Croatia
- Laboratoire de Physique Théorique de la Matiére Condensée (UMR CNRS 7600), Sorbonne Université, 4 Place Jussieu, Paris CEDEX 05 F75252, France
| | - Aurélien Perera
- Laboratoire de Physique Théorique de la Matiére Condensée (UMR CNRS 7600), Sorbonne Université, 4 Place Jussieu, Paris CEDEX 05 F75252, France
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Yamaguchi T. Shear Thinning and Nonlinear Structural Deformation of Ionic Liquids with Long Alkyl Chains Studied by Molecular Dynamics Simulation. J Phys Chem B 2019; 123:6260-6265. [PMID: 31259551 DOI: 10.1021/acs.jpcb.9b03557] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Nonequilibrium molecular dynamics (MD) simulation was performed on imidazolium-based ionic liquids of two different alkyl chain lengths, and shear-rate-dependent viscosity was evaluated. Compared with the frequency-dependent linear shear viscosity determined by equilibrium MD simulation, shear thinning occurs at the shear rate several times lower than that predicted by the Cox-Merz rule. The deformation of the structure factor was also evaluated as the function of shear rate. The onset of shear thinning corresponds to that of the nonlinearity in the deformation of the charge-alternation mode in both ionic liquids, which is in harmony with the result of our previous work that the shear relaxation of ionic liquids is mainly coupled to the structural relaxation of the charge-alternation mode. In the presence of the polar-nonpolar domain structure characteristic to ionic liquids with a long alkyl chain, in particular, the nonlinearity in the domain mode begins within the Newtonian regime of shear viscosity.
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Affiliation(s)
- Tsuyoshi Yamaguchi
- Graduate School of Engineering , Nagoya University , Furo-cho, Chikusa, Nagoya , Aichi 464-8603 , Japan
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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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Clustering in complex ionic liquids in two dimensions. J Mol Liq 2018. [DOI: 10.1016/j.molliq.2018.05.133] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Perera A, Lovrinčević B. A comparative study of aqueous DMSO mixtures by computer simulations and integral equation theories. Mol Phys 2018. [DOI: 10.1080/00268976.2018.1483040] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
Affiliation(s)
- Aurélien Perera
- Laboratoire de Physique Théorique de la Matiére Condensée (UMR CNRS 7600), Université Pierre et Marie Curie, Paris, France
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Longitudinal optic excitations in ionic melts within an ion-polarization model: A theoretical study. J Mol Liq 2018. [DOI: 10.1016/j.molliq.2018.03.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Daly RP, Araque JC, Margulis CJ. Communication: Stiff and soft nano-environments and the “Octopus Effect” are the crux of ionic liquid structural and dynamical heterogeneity. J Chem Phys 2017; 147:061102. [DOI: 10.1063/1.4990666] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Ryan P. Daly
- Department of Chemistry, University of Iowa, Iowa City, Iowa 52242, USA
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Abstract
Aqueous mixtures of small molecules, such as lower n-alkanols for example, are known to be micro-segregated, with domains in the nano-meter range.
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Affiliation(s)
- Aurélien Perera
- Laboratoire de Physique Théorique de la Matière Condensée (UMR CNRS 7600)
- Université Pierre et Marie Curie
- Paris cedex 05
- France
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Požar M, Kerasidou A, Lovrinčević B, Zoranić L, Mijaković M, Primorac T, Sokolić F, Teboul V, Perera A. The microscopic structure of cold aqueous methanol mixtures. J Chem Phys 2016; 145:144502. [DOI: 10.1063/1.4964487] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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Yamaguchi T. Mode-coupling theoretical study on the roles of heterogeneous structure in rheology of ionic liquids. J Chem Phys 2016; 144:124514. [PMID: 27036468 DOI: 10.1063/1.4944679] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Theoretical calculations of the rheological properties of coarse-grained model ionic liquids were performed using mode-coupling theory. The nonpolar part of the cation was systematically increased in order to clarify the effects of the heterogeneous structure on shear viscosity. The shear viscosity showed a minimum as the function of the size of the nonpolar part, as had been reported in literatures. The minimum was ascribed to the interplay between the increase in the shear relaxation time and the decrease in the high-frequency shear modulus with increasing the size of the nonpolar part of the cation. The ionic liquids with symmetric charge distribution of cations were less viscous than those with asymmetric cations, which is also in harmony with experiments. The theoretical analysis demonstrated that there are two mechanisms for the higher viscosity of the asymmetric model. The first one is the direct coupling between the domain dynamics and the shear stress. The second one is that the microscopic dynamics within the polar domain is retarded due to the nonlinear coupling with the heterogeneous structure.
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Affiliation(s)
- Tsuyoshi Yamaguchi
- Department of Molecular Design and Engineering, Graduate School of Engineering, Furo-cho B2-3 (611), Chikusa, Nagoya, Aichi 464-8603, Japan
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Abstract
AbstractConcentration fluctuations play an important role in the statistical description of the stability of liquids, particularly in the neighborhood of phase transitions. Classical thermodynamics is blind to fluctuations, and statistical thermodynamics is required to fully understand quantities such as the isothermal compressibility or heat capacity, by linking them to fluctuations of appropriate statistical microscopic quantities and showing that they are response functions. This is illustrated by the seminal Kirkwood–Buff theory of solutions. However, the existence of micro-heterogeneous structures, particularly in aqueous mixtures, which leads to large Kirkwood–Buff integrals, suggest that micro-heterogeneity is a form of concentration fluctuation. This interpretation becomes difficult to accept when extrapolated to larger micro-heterogeneous structures such as micellar aggregates in micro-emulsions. By analyzing how different methods, experimental, computer experiments and theoretical approaches deal with the underlying duality behind these two physical manifestations, we put in evidence the need to reconsider the description of liquids by incorporating the description of emergent “objects”, such as the micro-heterogeneous structures from a molecular point of view. On this path, the concept of “molecular emulsion” allows to describe in a unified way all type of disordered liquids, from solutions to the organized liquids of soft matter.
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Affiliation(s)
- Aurélien Perera
- 1Laboratoire de Physique Théorique de la Matière Condensée (UMR CNRS 7600), Université Pierre et Marie Curie, 4 Place Jussieu, F75252, Paris cedex 05, France
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Markiv B, Tokarchuk M. Effect of ion polarization on longitudinal excitations in ionic melts. J Chem Phys 2015; 143:194509. [PMID: 26590544 DOI: 10.1063/1.4935887] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
A simplified model for a collective dynamics in ionic melts is proposed for the description of optic-like excitations. Within a polarization model of ionic melt, the analytical expressions for optic and relaxation dipole modes are obtained. The considered model allows one to describe a softening of frequency and an increase of damping of optic modes caused by polarization processes in comparison with the rigid-ion model. The contributions related with ion polarization to time correlation functions are calculated.
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Affiliation(s)
- B Markiv
- Institute for Condensed Matter Physics of the National Academy of Sciences of Ukraine, 1 Svientsitskii Str., 79011 Lviv, Ukraine
| | - M Tokarchuk
- Institute for Condensed Matter Physics of the National Academy of Sciences of Ukraine, 1 Svientsitskii Str., 79011 Lviv, Ukraine
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Bores C, Lomba E, Perera A, Almarza NG. Pattern formation in binary fluid mixtures induced by short-range competing interactions. J Chem Phys 2015; 143:084501. [PMID: 26328850 DOI: 10.1063/1.4928524] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Molecular dynamics simulations and integral equation calculations of a simple equimolar mixture of diatomic molecules and monomers interacting via attractive and repulsive short-range potentials show the existence of pattern formation (microheterogeneity), mostly due to depletion forces away from the demixing region. Effective site-site potentials extracted from the pair correlation functions using an inverse Monte Carlo approach and an integral equation inversion procedure exhibit the features characteristic of a short-range attractive and a long-range repulsive potential. When charges are incorporated into the model, this becomes a coarse grained representation of a room temperature ionic liquid, and as expected, intermediate range order becomes more pronounced and stable.
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Affiliation(s)
- Cecilia Bores
- Instituto de Química Física Rocasolano, CSIC, Serrano 119, E-28006 Madrid, Spain
| | - Enrique Lomba
- Instituto de Química Física Rocasolano, CSIC, Serrano 119, E-28006 Madrid, Spain
| | - Aurélien Perera
- Laboratoire de Physique Théorique de la Matiére Condensée (UMR CNRS 7600), Université Pierre et Marie Curie, 4 Place Jussieu, F75252 Paris Cedex 05, France
| | - Noé G Almarza
- Instituto de Química Física Rocasolano, CSIC, Serrano 119, E-28006 Madrid, Spain
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