Condensed Matter Physics
https://cmpj2.icmp.lviv.ua/index.php/cmpj
<p><strong>Condensed Matter Physics</strong> contains original and review articles in the field of statistical mechanics and thermodynamics of equilibrium and nonequilibrium processes, relativistic mechanics of interacting particle systems.The main attention is paid to physics of solid, liquid and amorphous systems, phase equilibria and phase transitions, thermal, structural, electric, magnetic and optical properties of condensed matter. <strong>Condensed Matter Physics </strong>is a diamond open-access, international peer-reviewed scientific journal published quarterly.</p> <p><span id="main"><strong><tt>ISSN 1607-324X (print), 2224-9079 (online)</tt></strong></span></p> <p>Key title: <strong>Condensed Matter Physics</strong><br />Abbreviated key title: <strong>Condens. Matter Phys.</strong> </p>encmp@icmp.lviv.ua (CMP Editorial Office)ol@icmp.lviv.ua (Olena Dmytriieva (technical editor))Sat, 29 Jun 2024 16:07:32 +0000Open Journal Systems 3.4.0.5http://blogs.law.harvard.edu/tech/rss60Hamiltonian limited valence model for liquid polyamorphism
https://cmpj2.icmp.lviv.ua/index.php/cmpj/article/view/48
<p>Liquid-liquid phase transitions have been found experimentally or by computer simulations in many compounds such as water, hydrogen, sulfur, phosphorus, carbon, silica, and silicon. Limited valence model implemented via event-driven molecular dynamics algorithm provides a simple generic mechanism for the liquid-liquid phase transitions in all these diverse cases. Here, we introduce a variant of the limited valence model with a well defined Hamiltonian, i.e., a unique algorithm by which the potential energy of the system of particles can be computed solely from the coordinates of the particles and is thus equivalent to a complex multi-body potential. We present several examples of the model which can be used to reproduce liquid--liquid phase transition in systems with maximum valence <em>z</em> = 1 (hydrogen), <em>z</em> = 2 (sulfur) and <em>z</em> = 4 (water), where <em>z</em> is the maximum number of bonds an atom is allowed to have. For <em>z</em> = 1, we find a set of parameters for which the system has a liquid-liquid and an isostructural solid-solid critical points. For <em>z</em> = 4, we find a set of parameters for which the phase diagram resembles that of water with a wide region of negative thermal expansion coefficient (density anomaly) extending into the metastable region of negative pressures. The limited valence model can be modified to forbid not only too large valences but also too low valences. In the case of sulfur, we forbid the formation of monomers, thus restricting the valence v of an atom to be within an interval 1 = <em>v</em><sub>min </sub>≤ <em>v</em> ≤ <em>v</em><sub>max </sub>≡ z = 2.</p>
S. V. BuldyrevArticlesSoft Matterliquid-liquid phase transitionliquid-gas phase transitionsolid-solid transformationsphase diagrams
Copyright (c) 2024 S. V. Buldyrev
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https://cmpj2.icmp.lviv.ua/index.php/cmpj/article/view/48Fri, 28 Jun 2024 00:00:00 +0000Vapour-liquid phase behaviour of primitive models of ionic liquids confined in disordered porous media
https://cmpj2.icmp.lviv.ua/index.php/cmpj/article/view/49
<p>We develop a theory for the description of ionic liquids (ILs) confined in a porous medium formed by a matrix of immobile randomly placed uncharged particles. The IL is modelled as an electroneutral mixture of hard-sphere anions and flexible linear chain cations, represented by tangentially bonded hard spheres with the charge located on one of the terminal beads. The theory combines a generalization of the scaled particle theory, Wertheim's thermodynamic perturbation theory, and the associative mean-spherical approximation and allows one to obtain analytical expressions for the pressure and chemical potentials of the matrix-IL system. Using the theory, we calculate the vapour–liquid phase diagrams for two versions of the IL model, i.e., when the cation is modelled as a dimer and as a chain, in a complete association limit. The effects of the matrix confinement and of the non-spherical shape of the cations on the vapour-liquid phase diagrams are studied.</p>
T. Hvozd, T. Patsahan, Yu. Kalyuzhnyi, O. Patsahan, M. HolovkoArticlesSoft Matterionic liquidsdisordered porous mediumchain-like cationsvapour-liquid phase diagrams
Copyright (c) 2024 T. Hvozd, T. Patsahan, Yu. Kalyuzhnyi, O. Patsahan, M. Holovko
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https://cmpj2.icmp.lviv.ua/index.php/cmpj/article/view/49Fri, 28 Jun 2024 00:00:00 +0000Plasmonic effects in rod-like metal-dielectric nanoparticles
https://cmpj2.icmp.lviv.ua/index.php/cmpj/article/view/50
<p>The optical properties of rod-like two-layer nanoparticles are studied using the notions of equivalent prolate spheroid. The calculations are presented for frequency dependencies for polarizability and the absorption and scattering cross-section of prolate spheroids, cylinders, and spherocylinders. The effect of the sizes, the shapes of the nanoparticle and the material of the core and the shell on the location of the maxima of the imaginary part of polarizability and absorption and scattering cross-sections is analysed. The recommendations regarding the shape and size ratio of the nanoparticles for obtaining the maximum value of radiation efficiency are formulated.</p>
Ya. V. KarandasArticlesSolid State Physicspolarizabilityequivalent prolate spheroidfrequency dependenciesabsorption and scattering cross-sectionsrod-like nanoparticles
Copyright (c) 2024 Ya. V. Karandas
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https://cmpj2.icmp.lviv.ua/index.php/cmpj/article/view/50Fri, 28 Jun 2024 00:00:00 +0000The local structure, electronic and optical properties of Pb(Mg1/3Nb2/3)O3-PbTiO3: first-principles study
https://cmpj2.icmp.lviv.ua/index.php/cmpj/article/view/51
<p>Pb(Mg<sub>1/3</sub>Nb<sub>2/3</sub>)O<sub>3</sub>-PbTiO<sub>3</sub> perovskite-based crystals attract considerable scientific interest due to their interesting properties and possible use in piezoelectricity and photovoltaics. To understand the local structure and fundamental properties of such materials, in this work, we focused on the study within the density functional theory of structural, electronic, and optical properties of Pb[(Mg<sub>1/3</sub>Nb<sub>2/3</sub>)<sub>0.75</sub>Ti<sub>0.25</sub>]O<sub>3</sub>. Using GGA(PBEsol) approximation for structure optimization gives a good agreement with experimental data. Through the variation in Hubbard <em>U</em> parameters to GGA(PBEsol) functional, we achieve the bandgap for the Pb[(Mg<sub>1/3</sub>Nb<sub>2/3</sub>)<sub>0.75</sub>Ti<sub>0.25</sub>]O<sub>3</sub> which is in good agreement with the experimental results. The study of the bond populations showed that the Mg-O bond demonstrates no covalency, whereas there is a significant Ti-O and Nb-O covalent bonding. Such different bonding characteristics must be responsible for the relaxor properties of Pb[(Mg<sub>1/3</sub>Nb<sub>2/3</sub>)<sub>0.75</sub>Ti<sub>0.25</sub>]O<sub>3</sub> compound. In addition, the investigations of the optical properties of the Pb[(Mg<sub>1/3</sub>Nb<sub>2/3</sub>)<sub>0.75</sub>Ti<sub>0.25</sub>]O<sub>3</sub> by adopting Hubbard <em>U</em> corrections, modifying the error of the GGA approximation, and confirming the electronic analysis, were performed.</p>
M. Kovalenko, O. Bovgyra, V. Kapustianyk, O. KozachenkoArticlesComputer Modellinglocal structurebandgapdensity of statesoptical properties
Copyright (c) 2024 M. Kovalenko, O. Bovgyra, V. Kapustianyk, O. Kozachenko
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https://cmpj2.icmp.lviv.ua/index.php/cmpj/article/view/51Fri, 28 Jun 2024 00:00:00 +0000Spin-1/2 Ising-Heisenberg distorted diamond chain with antiferromagnetic Ising and ferromagnetic Heisenberg interactions
https://cmpj2.icmp.lviv.ua/index.php/cmpj/article/view/52
<p>The exactly solvable spin-1/2 Ising-Heisenberg distorted diamond chain in the presence of the external magnetic field is investigated for the case of antiferromagnetic Ising and ferromagnetic <em>XXZ</em> Heisenberg interactions. The influence of quantum fluctuations and the distortion on the ground state, magnetic and thermal properties of the model are studied in detail.In particular, it is established that the zero-temperature magnetization curve may involve intermediate plateaus just at zero and 1/3 of the saturation magnetization. It is demonstrated that the temperature dependence of the specific heat reveals up to four distinct peaks at zero magnetic field and up to five distinct peaks at a weak magnetic field. The physical origin of all observed additional peaks of the specific heat has been clarified on the grounds of dominating thermal excitations. We have shown that the quantum fluctuations give rise to an effective geometrical frustration in this chain.</p>
B. M. LisnyiArticlesSolid State PhysicsIsing-Heisenberg distorted diamond chainground statephase diagramspecific heat
Copyright (c) 2024 B. M. Lisnyi
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https://cmpj2.icmp.lviv.ua/index.php/cmpj/article/view/52Fri, 28 Jun 2024 00:00:00 +0000Hexagonal core-shell structure nanowire with high spins of spin-3/2 and spin-5/2
https://cmpj2.icmp.lviv.ua/index.php/cmpj/article/view/53
<p>The magnetic properties and hysteresis loops for the hexagonal Ising nanowire (HIN) with a core-shell structure consisting of mixed spins with the core spin being spin-5/2 and the shell spins being spin-3/2 are studied. The Blume-Capel model is considered by using the mean-field approximation (MFA) based on the Gibbs-Bogoliubov inequality for free energy. The impact of different bilinear interaction parameters (<em>J<sub>cc</sub>, J<sub>ss</sub>, J<sub>cs</sub></em>) between the core, shell, and core and shell spins, respectively, including the crystal (<em>D<sub>c</sub>, D<sub>s</sub></em>) and external magnetic fields (<em>h = h<sub>c</sub> = h<sub>s</sub></em>) at the core and shell sites, are taken into consideration. In order to obtain phase diagrams on various planes, the thermal changes of the net, core, and shell magnetizations are investigated for various values of our system parameters. It is discovered that the model exhibits only second-order phase transitions when <em>h</em> = 0.0 for <em>D</em> greater or equal to zero, first- and second-order phase transitions for <em>h</em> ≠ 0.0 and compensation temperatures for all <em>h</em>.</p>
M. Karimou, R. A. Yessoufou, E. AlbayrakArticlesSolid State Physicsmean field theoryBlume-Capel modelhysteresis loopscompensation temperaturemagnetizationmixed-spin system
Copyright (c) 2024 M. Karimou, R. A. Yessoufou, E. Albayrak
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https://cmpj2.icmp.lviv.ua/index.php/cmpj/article/view/53Fri, 28 Jun 2024 00:00:00 +0000Self-assembly behaviour of diblock copolymer-diblock copolymer under oscillating shear field
https://cmpj2.icmp.lviv.ua/index.php/cmpj/article/view/54
<p>The self-assembly behaviour of a diblock copolymer-diblock copolymer mixture under an oscillating shear field is investigated via cell dynamics simulation. The results indicate that the macrophase separation of the composite system is accompanied by the corresponding microphase separation induced by the oscillating shear field. With an increase in the shear frequency, the AB phase changes from a tilted layered structure to a parallel layered structure, and finally to a vertical layered structure. The CD phase transforms from the initial concentric ring into a parallel layer in the ring and then into a parallel layered structure; thus, the system finally forms a layered structure of the AB phase (vertical layer) and CD phase (parallel layer) perpendicular to each other. To verify the phase transition, the dynamic evolution of the domain size at different shear frequencies is analysed. The ordered phase transition with an increase in the oscillating shear field varies when the initial composition ratio of the system is changed. This conclusion provides a valuable guidance for the formation and transformation of ordered structures in experiments.</p>
Y. Guo, H. He, X. FuArticlesSoft Matterdiblock copolymeroscillating shear fieldself-assembly
Copyright (c) 2024 Y. Guo, H. He, X. Fu
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https://cmpj2.icmp.lviv.ua/index.php/cmpj/article/view/54Fri, 28 Jun 2024 00:00:00 +0000Molecular dynamics simulations of water-ethanol mixtures. I. Composition trends in thermodynamic properties
https://cmpj2.icmp.lviv.ua/index.php/cmpj/article/view/57
<p>We explored the composition dependence of a rather comprehensive set of properties of liquid water-ethanol mixtures by using the isobaric-isothermal molecular dynamics computer simulations. The united atom non-polarizable model from the TraPPE data basis for the ethanol molecule combined with the TIP4P-2005 and SPC/E water models is considered. We restrict our calculations to atmospheric pressure, 0.1013 MPa, and room temperature, 298.15 K. Composition trends of the behavior of density, excess mixing volume, apparent molar volumes are described. On the other hand, the excess mixing enthalpy and partial molar enthalpies of species are reported. Besides, we explore the coefficient of isobaric thermal expansion, isothermal heat capacity, adiabatic bulk modulus and heat capacity at constant pressure. In addition, the self-diffusion coefficients of species, the static dielectric constant and the surface tension are described. We intend to get insights into peculiarities of mixing of species in the mixture upon changes of ethanol molar fraction. The quality of predictions of the models is critically evaluated by detailed comparisons with experimental results. Then, necessary improvements of the modelling are discussed.</p>
D. Benavides Bautista, M. Aguilar, O. PizioArticlesComputer Modellingmolecular dynamicswater-ethanol mixturessurface tensiondielectric constantpartial molar volumes
Copyright (c) 2024 D. Benavides Bautista, M. Aguilar, O. Pizio
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https://cmpj2.icmp.lviv.ua/index.php/cmpj/article/view/57Fri, 28 Jun 2024 00:00:00 +0000The 70th Birthday of Professor Mykola Lebovka
https://cmpj2.icmp.lviv.ua/index.php/cmpj/article/view/56
<p>Professor Mykola Lebovka, an outstanding Ukrainian scientist in the field of physical chemistry of condensed matter, head of the Laboratory of Physical Chemistry of Disperse Minerals in F. D. Ovcharenko Institute of Biocolloidal Chemistry of National Academy of Sciences of Ukraine, the Editorial Board member of the Condensed Matter Physics journal, turns 70 on May 15, 2024.</p>
PersonaliaPersonalia
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https://cmpj2.icmp.lviv.ua/index.php/cmpj/article/view/56Fri, 28 Jun 2024 00:00:00 +0000The 75th Birthday of Professor Jurij Kozicki
https://cmpj2.icmp.lviv.ua/index.php/cmpj/article/view/55
<p>Professor Jurij Kozicki (a.k.a. Yurij Kozitsky), a renowned scholar in the field of mathematical backgrounds of statistical physics and dynamical systems, an active member of the Editorial board of the Condensed Matter Physics journal and a member of the Institute for Condensed Matter Physics Supervisory Board, celebrates his 75th Birthday.</p>
PersonaliaPersonalia
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https://cmpj2.icmp.lviv.ua/index.php/cmpj/article/view/55Fri, 28 Jun 2024 00:00:00 +0000In memory of Ihor Yukhnovskii, the founder and editor-in-chief of the journal ''Condensed Matter Physics'' (1925-2024)
https://cmpj2.icmp.lviv.ua/index.php/cmpj/article/view/46
<p>On March 26, 2024, the prominent Ukrainian scholar, theoretical physicist, and founder of the Lviv school of statistical physics, professor, academician of the National Academy of Sciences of Ukraine Ihor Yukhnovskii, passed away. He lived almost 99 years and his life was filled with many events. He was a soldier during World War II, a scientist and educator, and a public and state figure of the highest level. But above all, he was a scientist. He approached any task as a researcher, from formulating the problem to finding its optimal solution. Analytical thinking and mathematical logic dominated all his activities. At the same time, he remarkably combined scientific pragmatism with unexpected imaginative ideas, which ensured his outstanding achievements both in science and in politics.</p>
EditorialEditorial
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https://cmpj2.icmp.lviv.ua/index.php/cmpj/article/view/46Fri, 28 Jun 2024 00:00:00 +0000Effects of charge and size on the coadsorption of counterionic colloids in Gibbs monolayers
https://cmpj2.icmp.lviv.ua/index.php/cmpj/article/view/13
<p>This study uses a coarse-grained Monte Carlo algorithm to model and simulate the coadsorption of a binary mixture of counterionic colloids in Gibbs monolayers. These monolayers form at a idealized air-water interface, with one non-soluble species confined at the interface and the second one partially soluble in the aqueous phase. The investigation focuses on the effect of colloidal size and charge on the thermodynamics and microstructure of the monolayer. We find that the composition of the monolayer evolves non-trivially with surface coverage, depending on the balance of steric and electrostatic forces. When the electrostatic interactions are weak, the soluble species is expelled from the monolayer upon compression, yielding a phase behaviour particularly sensitive to the relative size of the soluble and non-soluble colloids. By contrast, strong electrostatic interactions favour the stabilization of the soluble particles in the monolayer and the formation of quasi-equimolar fluids, with only a weak dependence on particle size. The combination of these phenomena results in the formation of a number of two-dimensional mesoscopic arrangements in the monolayer, ranging from diluted gas-phase behaviour to domains of aggregates and percolates, and to incipient crystalline structures.</p>
J. M. Gómez-Verdú, B. Martínez-Haya, A. CuetosArticlesSoft MatterGibbs monolayersMonte Carloequations of stateaggregation
Copyright (c) 2024 J. M. Gómez-Verdú, B. Martínez-Haya, A. Cuetos
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https://cmpj2.icmp.lviv.ua/index.php/cmpj/article/view/13Thu, 28 Mar 2024 00:00:00 +0000Description of CuInP2S6 ferrielectrics in a mixed Ising model
https://cmpj2.icmp.lviv.ua/index.php/cmpj/article/view/44
<p>The appearance of spontaneous polarization in CuInP<sub>2</sub>S<sub>6</sub> ferrielectrics is related to the second order Jahn-Teller effect for copper cations located in a double-well local potential, the stereoactivity of indium cations located in a three-well local potential, as well as the valence fluctuations of phosphorus cations. The paraelectric to ferrielectric phase transition is primarily determined by the coupling of indium cations with their surroundings. This transition can be analyzed using the mixed Ising model with spins <em>s</em> = 1/2 and <em>S</em> = 1. The spectrum of pseudospin fluctuations at different temperatures was calculated using a mean-field approach for a set of quantum anharmonic oscillators. The results were then compared with Raman spectroscopy data for CuInP<sub>2</sub>S<sub>6</sub> crystal. The analysis indicates that the lattice anharmonicity below 150 K, is mainly determined by the indium sublattice, leading to the coexistence of the glassy state and ferrielectric phase. Above 150 K, the anharmonicity of the copper sublattice activates the ionic conductivity and results in the existence of a long-ranged fluctuated cluster of spontaneous polarization in a temperature interval of the paraelectric phase above <em>T<sub>C</sub></em>.</p>
R. Yevych, V. Liubachko, V. Hryts, M. Medulych, A. Kohutych, Yu. VysochanskiiRapid CommunicationSolid State PhysicsferrielectricsCuInP2S6mixed Ising modelquantum anharmonic oscillator model
Copyright (c) 2024 R. Yevych, V. Liubachko, V. Hryts, M. Medulych, A. Kohutych, Yu. Vysochanskii
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https://cmpj2.icmp.lviv.ua/index.php/cmpj/article/view/44Thu, 28 Mar 2024 00:00:00 +0000Computer simulations of soft matter. On 60-th anniversary of Jaroslav Ilnytskyi
https://cmpj2.icmp.lviv.ua/index.php/cmpj/article/view/43
<p>This special issue Condensed Matter Physics, entitled "Computer Simulations of Soft Matter" is dedicated to Jaroslav Ilnytskyi on the occasion of his 60-th birthday. Prof. J. Ilnytskyi is one of scientific leaders of the Institute for Condensed Matter Physics of the National Academy of Sciences of Ukraine (NASU), who iswell known for his contributions to the theory and computer simulation studies of polymer fluids, liquid crystals, macromolecular and colloid solutions. Versatility of Jaroslav works is due to his excellent background commonly resulting in original ideas, his feeling and ability to choose and apply appropriate methods for the solution of various problems. Finally, Jaroslav works are distinguished by the profound analyses of either theoretical or simulation results with respect to experimental observations frequently complemented by the discussion of possible applications.</p>
O. Pizio, T. Patsahan, V. BlavatskaEditorialEditorial
Copyright (c) 2024 O. Pizio, T. Patsahan, V. Blavatska
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https://cmpj2.icmp.lviv.ua/index.php/cmpj/article/view/43Thu, 28 Mar 2024 00:00:00 +0000Finite size effects and optimization of the calculation of the surface tension in surfactant mixtures at liquid/vapour interfaces
https://cmpj2.icmp.lviv.ua/index.php/cmpj/article/view/41
<p>The surface tension of monolayers with mixtures of anionic and nonionic surfactant at the liquid/vapour interface is studied. Previous works have observed that calculations of the surface tension of simple fluids show artificial oscillations for small interfacial areas, indicating that the surface tension data fluctuate due to the finite size effects and periodic boundary conditions. In the case of simulations of monolayers composed of surfactant mixtures, the surface tension not only oscillates for small areas but can also give non-physical data, such as negative values. Analysis of the monolayers with different surfactant mixtures, ionic (DTAB, CTAB, SDS) and nonionic (SB3-12), was done for density profiles, parameters of order and pair correlation functions for small and large box areas and all of them present similar behaviour. The fluctuations and the non-physical values of the surface tension are corrected when boxes with large interfacial areas are considered. The results indicate that in order to obtain reliable values of the surface tension, in computer simulations, it is important to choose not only the correct force field but also the appropriate size of the simulation box.</p>
C. J. Guzman-Valencia, J. Toriz-Salinas, H. Espinosa-Jimenez, A. B. Salazar-Arriaga, J. L. López-Cervantes, H. DominguezArticlesSoft Matterfinite size effectsmolecular dynamicssurface tensionsurfactant monolayer mixtureswater/air
Copyright (c) 2024 C. J. Guzman-Valencia, J. Toriz-Salinas, H. Espinosa-Jimenez, A. B. Salazar-Arriaga, J. L. López-Cervantes, H. Dominguez
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https://cmpj2.icmp.lviv.ua/index.php/cmpj/article/view/41Thu, 28 Mar 2024 00:00:00 +0000Dimerizing hard spherocylinders in porous media
https://cmpj2.icmp.lviv.ua/index.php/cmpj/article/view/39
<p>This research focuses on the unique phase behavior of non-spherical patchy colloids in porous environments. Based on the theory of scaled particle (SPT), methods have been refined and applied to analyze the thermodynamic properties of non-spherical patchy particles in a disordered porous medium. Utilizing the associative theory of liquids in conjunction with SPT, we investigated the impact of associative interactions and connections between the functional nodes of particles on the formation of the nematic phase. Calculations of orientational and spatial distributions were conducted, which helped to understand the phase behavior of particles during the transition from isotropic to nematic phase under the spatial constraints imposed by the disordered matrix of the porous medium.</p>
V. I. Shmotolokha, M. F. HolovkoArticlesSoft Matterpatchy colloidsspherocylindersdimerizationdisordered porous mediageometrical porosityprobe particle porosity
Copyright (c) 2024 V. I. Shmotolokha, M. F. Holovko
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https://cmpj2.icmp.lviv.ua/index.php/cmpj/article/view/39Thu, 28 Mar 2024 00:00:00 +0000When correlations exceed system size: ﬁnite-size scaling in free boundary conditions above the upper critical dimension
https://cmpj2.icmp.lviv.ua/index.php/cmpj/article/view/37
<p>We progress finite-size scaling in systems with free boundary conditions above their upper critical dimension, where in the thermodynamic limit critical scaling is described by mean-field theory. Recent works show that the correlation length is not bound by the system's physical size, a belief that long held sway. Instead, two scaling regimes can be observed — at the critical and pseudo-critical temperatures. We demonstrate that both are manifest for free boundaries. We use numerical simulations of the <em>d</em> = 5 Ising model to analyse the magnetization, susceptibility, magnetization Fourier modes and the partition function zeros. While some of the response functions hide the dual finite-size scaling, the precision enabled by the analysis of Lee–Yang zeros allows this be brought to the fore. In particular, finite-size scaling of leading zeros at the pseudo-critical point confirms recent predictions coming from correlations exceeding the system size. This paper is dedicated to Jaroslav Ilnytskyi on the occasion of his 60th birthday.</p>
Yu. Honchar, B. Berche, Yu. Holovatch, R. KennaArticlesStatistical Physicsuniversalityﬁnite-size scalingupper critical dimension
Copyright (c) 2024 Yu. Honchar, B. Berche, Yu. Holovatch, R. Kenna
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https://cmpj2.icmp.lviv.ua/index.php/cmpj/article/view/37Thu, 28 Mar 2024 00:00:00 +0000Universal properties of branched copolymers in dilute solutions
https://cmpj2.icmp.lviv.ua/index.php/cmpj/article/view/26
<p>We analyze the universal conformational properties of complex copolymer macromolecules, based on two topologies: the <em>rosette</em> structure containing f<sub>c</sub> linear branches and f<sub>r</sub> closed loops grafted to the central core, and the symmetric <em>pom-pom</em> structure, consisting of a backbone linear chain terminated by two branching points with functionalities <em>f</em>. We assume that the constituent strands (branches) of these structures can be of two different chemical species <em>a</em> and <em>b</em>. Depending on the solvent conditions, the inter- or intrachain interactions of some links may vanish, which corresponds to Θ-state of the corresponding polymer species. Applying both the analytical approach within the frames of direct polymer renormalization and numerical simulations based on the lattice model of polymer, we evaluated the set of parameters characterizing the size properties of constituent parts of two complex topologies and estimated quantitatively the impact of interactions between constituent parts on these size characteristics.</p>
K. Haydukivska, V. BlavatskaArticlesStatistical PhysicsSoft Matterpolymersscalinguniversal propertiesrenormalization groupnumerical simulations
Copyright (c) 2024 K. Haydukivska, V. Blavatska
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https://cmpj2.icmp.lviv.ua/index.php/cmpj/article/view/26Thu, 28 Mar 2024 00:00:00 +0000Percolation connectivity in deposits obtained usingcompetitive random sequential adsorption of binarydisk mixtures
https://cmpj2.icmp.lviv.ua/index.php/cmpj/article/view/25
<p>Connectedness percolation phenomena in the two-dimensional (2D) packing of binary mixtures of disks with different diameters were studied numerically. The packings were produced using random sequential adsorption (RSA) model with simultaneous deposition of disks. The ratio of the particle diameters was varied within the range D=1-10, and the selection probability of the small disks was varied within the range 0-1. A core-shell structure of the particles was assumed for the analysis of connectivity. The packing coverages in a jamming state for different components, connectivities through small, large and both types of disks, the behavior of electrical conductivity were analyzed. The observed complex effects were explained accounting for the formation of conductive "bridges" from small disks in pores between large disks. </p>
N. I. Lebovka, M. R. Petryk, N. V. VygornitskiiArticlesSoft Matterpackingjammingadsorptioncompetitiondepositionpercolation
Copyright (c) 2024 N. I. Lebovka, M. R. Petryk, N. V. Vygornitskii
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https://cmpj2.icmp.lviv.ua/index.php/cmpj/article/view/25Thu, 28 Mar 2024 00:00:00 +0000Toward a realistic model of multilayered bacterial colonies
https://cmpj2.icmp.lviv.ua/index.php/cmpj/article/view/23
<p>Bacteria are prolific at colonizing diverse surfaces under a widerange of environmental conditions, and exhibit fascinating examples of self-organization across scales. Though it has recently attracted considerable interest, the role of mechanical forces in the collective behavior of bacterial colonies is not yet fully understood. Here, we construct a model of growing rod-like bacteria, such as Escherichia coli based purely on mechanical forces. We perform overdamped molecular dynamics simulations of the colony starting from a few cells in contact with a surface. As the colony grows, microdomains of strongly aligned cells grow and proliferate. Our model captures both the initial growth of a bacterial colony and also shows characteristic signs of capturing the experimentally observed transition to multilayered colonies over longer timescales. We compare our results with experiments on E. coli cells and analyze the statistics of microdomains.</p>
M. T. Khan, J. Cammann, A. Sengupta, E. Renzi, M. G. MazzaArticlesSoft Matterbacteriaactive matterorientational ordergeometrymechanicsmono-to-multilayer transition
Copyright (c) 2024 M. T. Khan, J. Cammann, A. Sengupta, E. Renzi, M. G. Mazza
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https://cmpj2.icmp.lviv.ua/index.php/cmpj/article/view/23Thu, 28 Mar 2024 00:00:00 +0000Active microrheology of fluids with orientational order
https://cmpj2.icmp.lviv.ua/index.php/cmpj/article/view/22
<p>We study the dynamics of a driven spherical colloidal particle moving in a fluid with a broken rotational symmetry. Using a nematic liquid crystal as a model, we demonstrate that when the applied force is not aligned along or perpendicular to the orientational order, the colloidal velocity does not align with the force, but forms an angle with respect to the pulling direction. This leads to blue an anisotropic hydrodynamic drag tensor which depends on the material parameters. In the case of nematic liquid crystal, we give an analytical expression and discuss the resulting implications for active microrheology experiments on fluids with broken rotational symmetry.</p>
J. S. Lintuvuori, A. WürgerArticlesSoft Matterliquid crystalscolloids,microrheologylattice Boltzmann methods
Copyright (c) 2024 J. S. Lintuvuori, A. Würger
https://creativecommons.org/licenses/by/4.0
https://cmpj2.icmp.lviv.ua/index.php/cmpj/article/view/22Thu, 28 Mar 2024 00:00:00 +0000Revisiting the wetting behavior of solid surfaces by water-like models within a density functional theory
https://cmpj2.icmp.lviv.ua/index.php/cmpj/article/view/18
<p>We perform the analysis of predictions of a classical density functional theory for associating fluids with different association strength concerned with wetting of solid surfaces. The four associating sites water-like models with non-associative square-well attraction parametrized by Clark et al. [Mol. Phys., 2006, 104, 3561] are considered. The fluid-solid potential is assumed to have a 10-4-3 functional form. The growth of water film on the substrate upon changing the chemical potential is described. The wetting and prewetting critical temperatures, as well as the prewetting phase diagram are evaluated for different fluid-solid attraction strength from the analysis of the adsorption isotherms. Moreover, the temperature dependence of the contact angle is obtained from the Young equation. It yields estimates for the wetting temperature as well. Theoretical findings are compared with experimental results and in a few cases with data from computer simulations. The theory is successful and quite accurate in describing the wetting temperature and contact angle changes with temperature for different values of fluid-substrate attraction. Moreover, the method provides an easy tool to study other associating fluids on solids of importance for chemical engineering, in comparison with laboratory experiments and computer simulations.</p>
A. Kozina, M. Aguilar, O. Pizio, S. SokołowskiArticlesSoft Matterwatergraphitedensity functionalwettingadsorption
Copyright (c) 2024 A. Kozina, M. Aguilar, O. Pizio, S. Sokołowski
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https://cmpj2.icmp.lviv.ua/index.php/cmpj/article/view/18Thu, 28 Mar 2024 00:00:00 +0000Shape changes of a single hairy particle with mobile ligands at a liquid-liquid interface
https://cmpj2.icmp.lviv.ua/index.php/cmpj/article/view/17
<p>We investigate rearrangements of a single hairy particle at a liquid-liquid interface using coarse-grained molecular dynamics simulations. We consider the particles with the same (symmetrical interactions) and different (asymmetrical interactions) affinity to the liquids. We show how ligand mobility affects the behavior of the hairy particle at the liquid-liquid interface. We found that such a hairy particle can take various shapes at the interface. For example, a Janus-like snowman consisting of a segment cluster and a bare part of the core, Saturn-like structures, and the core with a wide “plume” on one side. A configuration of the particle at the interface is characterized by the vertical displacement distance and the orientation of the particle relative to the phase boundary. The selected descriptors are used to characterize the shape of the segment cloud. We found that the shape of a particle and its localization at the interface can be determined by tuning the interactions with the liquids.</p>
T. Staszewski, M. BorówkoArticlesSoft Matterhairy particlesparticle-laden layersmolecular dynamics
Copyright (c) 2024 T. Staszewski, M. Borówko
https://creativecommons.org/licenses/by/4.0
https://cmpj2.icmp.lviv.ua/index.php/cmpj/article/view/17Thu, 28 Mar 2024 00:00:00 +0000Editorial
https://cmpj2.icmp.lviv.ua/index.php/cmpj/article/view/20
EditorialEditorial
Copyright (c) 2024
https://creativecommons.org/licenses/by/4.0
https://cmpj2.icmp.lviv.ua/index.php/cmpj/article/view/20Thu, 28 Mar 2024 00:00:00 +0000