Condensed Matter Physics 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. Condensed Matter Physics is a diamond open-access, international peer-reviewed scientific journal published quarterly. ISSN 1607-324X (print), 2224-9079 (online) Key title: Condensed Matter Physics Abbreviated key title: Condens. Matter Phys.
Yukhnovskii Institute for Condensed Matter Physics of the National Academy of Sciences of Ukraine
The self-assembly behavior of a diblock copolymer/homopolymer induced by Janus nanorods
We employ cell dynamics simulation based on the CH/BD model to investigate the self-assembly behavior of a mixed system consisting of diblock copolymers (AB), homopolymers (C), and Janus nanorods. The results indicate that, at different component ratios, the mixed system undergoes various phase transitions with an increasing number of nanorods. Specifically, when the homopolymer component is 0.40, the mixed system transitions from a disordered structure to a parallel lamellar structure, subsequently to a tilted layered structure, and ultimately to a perpendicular lamellar structure as the number of nanorods increases. To explore this phenomenon in greater depth, we conduct a comprehensive analysis of domain sizes and pattern evolution. Additionally, we investigate the effects of the repulsive interaction strength between polymers, wetting strength, length of nanorods, and degree of asymmetry on the self-assembly behavior of the mixed system. This research provides significant theoretical and experimental insights for the preparation of novel nanomaterials.
Copyright (c) 2025 Y. Q. Guo, J. Liu, H. R. He, N. Wu, J. J. Zhang https://creativecommons.org/licenses/by/4.0
Algebraic solution and thermodynamic properties of graphene in the presence of minimal length
Graphene is a zero-gap semiconductor, where the electrons propagating inside are described by the ultrarelativistic Dirac equation normally reserved for very high energy massless particles. In this work, we show that graphene under a magnetic field in the presence of a minimal length has a hidden su(1, 1) symmetry. This symmetry allows us to construct the spectrum algebraically. In fact, a generalized uncertainty relation, leading to a non-zero minimum uncertainty on the position, would be closer to physical reality and allow us to control or create bound states in graphene. Using the partition function based on the Epstein zeta function, the thermodynamic properties are well determined. We find that the Dulong–Petit law is verified and the heat capacity is independent of the deformation parameter.
Copyright (c) 2025 J. Gbètoho, F. A. Dossa, G. Y. H. Avossevou https://creativecommons.org/licenses/by/4.0
Generalised two-dimensional nonlinear oscillator with a position-dependent effective mass and the thermodynamic properties
We investigate a two-dimensional nonlinear oscillator with a position-dependent effective mass in the framework of nonrelativistic quantum mechanics. Using the Nikiforov-Uvarov method, we obtain exact analytical expressions for the energy spectrum and wave functions. Based on the canonical partition function, we derive key thermodynamic quantities, including internal energy, specific heat, free energy, and entropy. Our results show that, unlike the one-dimensional case, where the specific heat is unaffected by the nonlinearity parameter k, the two-dimensional system exhibits a strong k−dependence. At high temperatures, the specific heat becomes temperature-independent for fixed values of k, in line with the Dulong–Petit law. However, these behaviors occur only for negative values of k. These findings highlight the impact of effective mass nonlinearity on macroscopic thermodynamic quantities and suggest that tuning the parameter k could serve as an effective strategy for enhancing the performance of quantum devices, including thermal machines and optoelectronic components.
Copyright (c) 2025 S. E. Bokpe, F. A. Dossa, G. Y. H. Avossevou https://creativecommons.org/licenses/by/4.0
Thermodynamic relation for the systems with inhomogeneous distribution of particles
For the system with inhomogeneous distribution of macroscopic parameters we obtain thermodynamic relation which depends on the spatial point(coordinate). In our approach, to obtain such a relation we use the basic ideas of the method of nonequilibrium statistical operator combined with the Hubbard–Stratonovich transformation. First of all, we define the thermodynamic relation for the system with homogeneous distribution of particles. Possible behavior peculiarities of systems with different character of interaction in nonequilibrium case are predicted. By saddle-point method we find the dominant contributions to the partition function and obtain all thermodynamic parameters of the systems with different character of interaction. The formations of saddle state in all systems of interacting particles at different temperatures and particle distributions have the same physical nature and therefore they can be described in the same way. We consider the systems with attractive and repulsive interactions as well as self-gravitating systems.
Сollection of the articles dedicated to the 100th anniversary of Prof. Ihor Yukhnovskii
Copyright (c) 2025 A. P. Rebesh, B. I. Lev, A.G. Zagorodny https://creativecommons.org/licenses/by/4.0
The influence of dimensional crossover on phase transitions and critical phenomena in condensed systems
This article is aimed at studying the effects of the dimensional crossover (DC) on physical properties of condensed systems near phase transition and critical points. Here we consider the following problems: (1) the theoretical provisions that allow to study the effect of spatial confinement on DC near phase transition and critical points; (2) the study of DC in condensed systems with the Ginzburg number Gi < 1, where fluctuation effects are described in different ways at the fluctuation, regular and intermediate (crossover) regions; (3) two types of DC were investigated: (a) a decrease in the linear dimensions L to the values of the correlation length of the order parameter fluctuations leads to the conversion of the dependence on thermodynamic variable into a dependence on linear sizes of 3D systems, as well as (b) a further decrease in linear sizes L the 3D–2D or 3D1D DC happens depending on slitlike or cylindrical geometry, which is determined by the value of the lower crossover dimensionality dLCD; (4) it is proposed to extend the known equalities for critical exponents by using the Mandelbrot formula for fractal dimension Df as a critical exponent; (5) the influence of 3D–2D DC on the characteristics of the fine structure of the molecular light scattering (MLS) spectrum is studied.
Copyright (c) 2025 O. V. Chalyi, E. V. Zaitseva https://creativecommons.org/licenses/by/4.0
Phase stability and structural properties of the KxCa1-xN novel ferromagnetic alloy from ﬁrst-principles
We study the structural properties and phase stability of the KxCa1−xN alloy using the regular-solution model based on the total energy of the mixing. The pseudopotential approach was used along with PBE functional of Perdew, Burke, and Ernzerhof (PBE). We investigated the bond-lengths distribution as a function of composition x. We also predicted the phase separation of the two partially miscible components and calculated the enthalpy ∆H using the interaction parameter Ω. We observe an asymmetry about x = 0.46 in the phase diagram due to the x-dependant interaction parameter Ω = 12.69 − 1.32x kcal/mole. The equilibrium solubility limit, known as the miscibility gap is found to be around 3033 K.
Copyright (c) 2025 K. Larbaoui, A. Lakdja, G. Bassou https://creativecommons.org/licenses/by/4.0
Beyond conventional half-metals: gapless states and spin gapless semiconducting behavior in X2MnGa (X =Ti, Ir) Heusler compounds
The search for high-performance spintronic materials motivates the exploration of Heusler alloys with unconventional electronic properties. Using density functional theory with Hubbard correction (DFT+U, U = 4 eV), we investigate X2MnGa (X = Ti, Ir) alloys, which stabilize in the ferromagnetic L21-type structure with strong thermodynamic stability. Electronic structure calculations reveal contrasting behaviors: Ti2MnGa transitions from a metallic L21-type phase to a spin gapless semiconductor (SGS) in the XA-type, while Ir2MnGa exhibits gapless half-metallicity behavior in the L21-type but becomes half-metallic in the XA-type. The magnetic properties are governed by spd hybridization between Mn-3d and X-d/Ga-p states, which stabilizes ferromagnetism and tailors electronic states near the Fermi level. The Hubbard U correction proves essential for accurately describing the correlated Mn-3d electrons. These alloys combine structural stability with tunable electronic and magnetic properties, offering a promising platform for spin-polarized transport in next-generation spintronic devices.
Copyright (c) 2025 N. Bouteldja, N. Hacini, I. Ouadha, H. Rached https://creativecommons.org/licenses/by/4.0
Tripartite entanglement in mixed-spin triangle trimmer
Heisenberg model spin systems offer favourable and manageable physical settings for generating and manipulating entangled quantum states. In this work mixed spin-(1/2,1/2,1) Heisenberg spin trimmer with two different but isotropic Landé g-factors and two different exchange constants is considered. The study undertakes the task of finding the optimal parameters to create entangled states and control them by external magnetic field. The primary objective of this work is to examine the tripartite entanglement of a system and the dependence of the tripartite entanglement on various system parameters. Particularly, the effects of non-conserving magnetization are in the focus of our research. The source of non-commutativity between the magnetic moment operator and the Hamiltonian is non-uniformity of g-factors. To quantify the tripartite entanglement, an entanglement measure refered to as “tripartite negativity” has been used in this work.
Copyright (c) 2025 Zh. Adamyan, V. Ohanyan https://creativecommons.org/licenses/by/4.0
Liquid-gas state regularities as a manifestation of global isomorphism with the Ising model
Liquid-gas equilibrium is considered using the global isomorphism with the Ising-like (lattice gas) model. Such an approach assumes the existence of the order parameter in terms of which the symmetry of binodal is restored not only in the vicinity of the critical point (critical isomorphism) but also globally in the whole coexistence region. We show how the empirical law of the rectilinear density diameter of the liquid-gas binodal allows us to derive a rather simple form of the isomorphism transformation between the fluid and lattice gas model of Ising-type. The relations for critical parameters which follow from such isomorphism are tested on a variety of fluid systems, both real and model ones. Moreover, we consider the phase equilibrium in polymer solutions and the Flory θ-point as the extreme state of such equilibrium within our approach. The most crucial testing in 2D case is using the Onsager exact solution of the Ising model, and we represent the results of our approach to the calculation of critical point parameters of monolayers for noble gases and the surface tension.
Copyright (c) 2025 L. A. Bulavin, V. L. Kulinskyi, A. M. Katts, A. M. Maslechko https://creativecommons.org/licenses/by/4.0
Statistical theory of charged particle systems including triple bound states — and the Collaboration Lviv–Rostock
Honoring the hundredth anniversary of the birthday of Ihor R. Yuknovskii we analyze new developments in the statistical thermodynamics of Coulomb systems. The basic idea of this work is to demonstrate that the exponential potential used in the first papers of Yukhnovskii is an appropriate reference system for a description of classical and quantum charged particle systems. We briefly discuss the collaboration between the groups of Ihor R. Yuknovskii in Lviv and Günter Kelbg in Rostock and analyze several approaches based on pair correlation functions and cluster expansion in the classical as well as in the quantum case. Finally, we discuss the progress in the statistical description of bound states of three particles as in helium plasmas and in MgCl2-solutions in the classical case and present new results regarding the influence of three-particle bound states. In particular, we give new expressions for the cluster integrals and the mass action functions of helium atoms and ionic triple associates as well as for the equation of state (EoS).
Copyright (c) 2025 W. Ebeling https://creativecommons.org/licenses/by/4.0
Mutual effect of charge- and number-density correlations in ionic liquids and concentrated electrolytes
Correlation functions in concentrated ionic systems are studied within the mesoscopic theory at the level of the Gaussian approximation. The previously neglected fluctuation contribution to the inverse charge-charge correlation function is taken into account to verify the accuracy of the previous results. We calculate the correlation lengths and the amplitudes and show that the fluctuation contribution does not lead to significant changes of the results. We also derive necessary conditions for the presence of both, the oscillatory and the monotonic decays of the charge-charge correlations that must be satisfied by the noncoulombic contributions to the inverse charge-charge correlation function. At the level of the Gaussian approximation, these conditions are not satisfied. Extension of the theory beyond the Gaussian approximation is necessary to verify whether the asymptotic decay of the charge-charge correlations is monotonous or oscillatory, as suggested by the surface force apparatus or by the SAXS experiments, respectively.
Copyright (c) 2025 O. Patsahan, A. Ciach https://creativecommons.org/licenses/by/4.0
Replica RISM molecular solvation theory for electric double layer in nanoporous materials
Applications of 3D-RISM-KH molecular solvation theory range from solvation energy of small molecules to phase behavior of polymers and biomolecules. It predicts the molecular mechanisms of chemical and biomolecular systems. Replica RISM-KH-VM molecular solvation theory predicts and explains the structure, thermodynamics, and electrochemistry of electrolyte solutions sorbed in a nanoporous material. It was tested on nanoporous carbon supercapacitors with aqueous electrolyte and nanoporous electrosorption cells. The mechanisms in these systems are steered by the electric double layer potential drop across the Stern layer at the nanopores surface and the Gouy-Chapman layer averaged over the nanoporous material, the osmotic term due to the ionic concentrations difference in the two nanoporous electrodes and in the electrolyte solution outside, and the solvation chemical potentials of sorbed ions averaged over the nanoporous material. The latter strongly depends on chemical specificity of ions, solvent, surface functional groups, and steric effects for solvated ions confined in nanopores.
Copyright (c) 2025 A. Kovalenko https://creativecommons.org/licenses/by/4.0
Effective and asymptotic scaling in a one-dimensional billiard problem
The emergence of power laws that govern the large-time dynamics of a one-dimensional billiard of N point particles is analysed. In the initial state, the resting particles are placed in the positive half-line x ≥ 0 at equal distances. Their masses alternate between two distinct values. The dynamics is initialized by giving the leftmost particle a positive velocity. Due to elastic inter-particle collisions, the whole system gradually comes into motion, filling both right-hand and left-hand half-lines. As shown by [Chakraborti S., Dhar A., Krapivsky P., SciPost Phys., 2022, 13, 074], an inherent feature of such a billiard is the emergence of two different modes: the shock wave that propagates in x ≥ 0 and the splash region in x < 0. Moreover, the behaviour of the relevant observables is characterized by universal asymptotic power-law dependencies. In view of the finite size of the system and of finite observation times, these dependencies only start to acquire a universal character. To analyse them, we set up molecular dynamics simulations using the concept of effective scaling exponents, familiar in the theory of continuous phase transitions. We present results for the effective exponents that govern the large-time behaviour of the shock-wave front, the number of collisions, the energies and momentum of different modes and analyse their tendency to approach corresponding universal values.
Copyright (c) 2025 T. Holovatch, Yu. Kozitsky, K. Pilorz, Yu. Holovatch https://creativecommons.org/licenses/by/4.0
Method of canonical transformations in the theory of quantum gases interacting with radiation
An approach to the theoretical study of effects and phenomena in quantum gases interacting with radiation is proposed. The approach is based on a modification of the canonical transformation method, which was once used to diagonalize Hamiltonians describing the interaction of electrons with phonons in a solid. The capabilities of the method are demonstrated by studying the influence of photons on the spectral characteristics of atoms of quantum gases interacting with radiation. Within the framework of the developed approach, the effect of “dressing” atoms of quantum gases by a cloud of virtual photons is investigated and expressions for the energy characteristics of such dressed atoms — quasiparticles are obtained. The problem of defining the concept of the effective mass of such quasiparticles is discussed.
Copyright (c) 2025 M. S. Bulakhov, A. S. Peletminskii, P. P. Kostrobij, I. A. Ryzha, Yu. V. Slyusarenko https://creativecommons.org/licenses/by/4.0
Excluded volume effect of surfactant ligands on the shape of nascent nanocrystal
We investigate the effect of the excluded volume of surfactant ligands on the shape of incipient quantum dots (QDs) to which they are attached. We consider a model in which ligands are represented by hard-sphere particles that are bound to the surface of a nanoparticle (NC) that is cast in the shape of a prism. It is found in Monte Carlo simulations that the ensemble of relevant NC conformations consists of a small number of specific states that take on the form of nanoplates and nanorods. The shape of these states can be well described by the derived theoretical models. At increasing ligand density, the free energy of different states is seen to be approximately the same, suggesting that excluded volume interactions among ligands acts to narrow down the conformational space accessible to an NC without creating a statistical preference for any particular configuration.
Copyright (c) 2025 A. Baumketner, D. Anokhin, Ya. Patsahan https://creativecommons.org/licenses/by/4.0
A consistent description of the kinetic processes of electrolyte ion transport in a dynamic porous medium
The consistent description of kinetic and hydrodynamic processes is applied to the study of ion transport processes in the ionic solution-porous medium system. A system of equations is obtained for the nonequilibrium single-ion distribution function, the nonequilibrium average value of the energy density of the interaction of solution ions, and the nonequilibrium average value of the number density of particles in a porous medium. Using the fractional calculus technique, a generalized diffusion equation of the Cattaneo type in fractional derivatives is obtained to describe the processes of subdiffusion of particles in a porous medium.
Copyright (c) 2025 P. P. Kostrobij, B. M. Markovych, O. V. Viznovych, M. V. Tokarchuk https://creativecommons.org/licenses/by/4.0
Elastic properties of fluid mercury across the metal-nonmetal transition: Ab initio simulation study
We report an ab initio molecular dynamics study of fluid mercury at temperature 1750 K in the range of densities 7–13.5 g/cm3 . Along this isothermal line we performed an analysis of total charge fluctuations, which make evidence of neutral atom-like screening in fluid Hg for densities less than 9.25 g/cm3 , which practically coincides with the emergence of the gap in electronic density of states. High-frequency shear modulus, high-frequency and adiabatic speeds of sound, shear viscosity, Maxwell relaxation time and dispersion of collective excitations are analyzed as a function of density along the isothermal line.
Copyright (c) 2025 T. Bryk, O. Bakai, A. P. Seitsonen https://creativecommons.org/licenses/by/4.0
On the diffusion of hard sphere fluids in disordered porous media: New extended Enskog theory description
We proposed a new extended version of Enskog theory for the description of the self-diffusion coefficient of a colloidal hard-sphere fluid adsorbed in a matrix of disordered hard-sphere obstacles. In a considered approach instead of contact values of the fluid-fluid and fluid-matrix pair distribution functions, we introduced by input the new functions that include the dependence on the fraction of the volume free from matrix particles and from fluid particles trapped by matrix particles. It is shown that the introduction of this free volume fraction by the Fermi-like distribution leads to the best agreement between theoretical predictions and computer simulation results [Chang R., Jagannathan K., Yethiraj A., Phys. Rev. E, 2004, 69, 051101].
Copyright (c) 2025 M. Ya. Korvatska, M. F. Holovko https://creativecommons.org/licenses/by/4.0
Towards construction of microscopic model for smart coating of a solid surface
The density functional approach for classical associating fluids is used to explore the wetting phase diagrams for model systems consisting of water and graphite-like solid surfaces chemically modified by a small amount of grafted chain molecules. The water-like fluid model is adopted from the work of Clark et al. [Mol. Phys., 104, 3561 (2006)]. It very well describes the bulk water vapor-liquid coexistence. Each chain molecule consists of tangentially bonded hard sphere segments. We focus on the investigation of the growth of water film on such complex substrates and exploration of the wetting behavior. For grafted monomers, the prewetting phase diagrams are similar to the diagrams for water on a non-modified solid surface. However, for grafted trimers and pentamers, a physically much richer behavior is observed and analyzed. Trends of the behavior of the wetting temperature and the prewetting critical temperature on the grafting density and water-segments attraction are discussed in detail.
Copyright (c) 2025 O. Pizio https://creativecommons.org/licenses/by/4.0
Founder of the Lviv School of Statistical Physics and Builder of Ukrainian Statehood. To the Centenary of Ihor Yukhnovskii’ Birth (01.09.1925-26.03.2024)
September 1, 2025 marks the 100th anniversary of the birth of one of the Founding Fathers of the renewed Ukrainian state, a prominent Ukrainian scientist, theoretical physicist, founder of the modern Lviv school of statistical physics, Professor, full member of the National Academy of Sciences of Ukraine, full and honorary member of the Shevchenko Scientific Society, Hero of Ukraine, Ihor Yukhnovskii. He completed his earthly journey on March 26, 2024, in his 99th year of life. At the end of his eventful life, he pondered: “And now I no longer know what was most important to me in life — physics or politics?” Let us reflect on this issue as well.
Copyright (c) 2025 W. Ebeling, Yu. Holovatch, M. Holovko, I. Mryglod, O. Patsahan https://creativecommons.org/licenses/by/4.0
Copyright (c) 2025 https://creativecommons.org/licenses/by/4.0
Making science for the future and studying its past. To the 80th Birthday of Reinhard Folk
Description processes of the interaction of water and aqueous solutions with fuel-containing materials in the New Safe Confinement of the “Shelter” object
The main mechanisms and conditions of interaction of lava-like fuel-containing materials (LFCM) with the atmosphere, water and aqueous solutions are presented. The mechanisms of destruction of the LFCM surface, including ion-exchange processes, hydrolysis, dissolution, oxidation, etc., were analyzed. Inhomogeneous diffusion coefficients for UO22+, Cs+ ions at the interface “aqueous solution of radioactive elements – LFCM” were calculated. The interdiffusion processes and the rate of penetration into the porous medium of the reaction front of the internal hydrolysis of the silicon-oxygen network during interaction with an aqueous solution were analyzed, where the reaction and adsorption processes are hidden in the rate of internal hydrolysis.
Copyright (c) 2025 M. Tokarchuk, B. Markovych, O. Zakharyash, O. Ivankiv, S. Mokhniak https://creativecommons.org/licenses/by/4.0
Cahn-Hilliard model with Schlögl Reactions: interplay of equilibrium and non-equilibrium phase transitions. II. Memory effects
The present work is a continuation of our previous paper [Condens. Matter Phys., 2020, 23, 33602: 1–17]. It is devoted to the modelling of the interplay of equilibrium and non-equilibrium phase transitions. The modelling of equilibrium phase transition is based on the modified Cahn–Hilliard equation. The non-equilibrium phase transition is modeled by the Second Schlögl reaction system. We consider the advancing front, which combines these both transitions. Different from the first article, we consider here the memory effects, i.e., the effects of non-Fickian diffusion. The traveling wave solution is obtained, and its dependence on the model parameters is studied in detail. The relative importance of memory effects for different process regimes is estimated.
Copyright (c) 2025 P. Mchedlov-Petrosyan, L. Davydov https://creativecommons.org/licenses/by/4.0
Entropy of a restricted primitive model electrolyte using a mean electrostatic potential approach
The excess entropy of restricted primitive model electrolytes is calculated using a potential based approach through the symmetric Poisson-Boltzmann and the modified Poisson-Boltzmann theories. The theories are utilized in conjunction with a statistical thermodynamics equation that is shown to be equivalent to thermodynamic integration. Electrolyte systems having ionic valencies 1:1 and 2:2 with diameters 3 × 10−10 m and 4.25 ×10−10 m are treated over a wide range of concentrations. The exact radial distribution functions for the model electrolytes obtained from Monte Carlo simulations in the canonical ensemble are compared with the corresponding theoretical predictions. Furthermore, the radial distribution functions from the theories and the simulations are used in the Laird-Haymet entropy expansion equations [ J. Chem. Phys., 1994, 100, 3775] to estimate the excess entropy of the solutions. These equations take into account multi-particle distribution functions, which are approximated using a “ring” term. In general, the modified Poisson-Boltzmann theory gives results that are more consistent with the simulation data than those from the symmetric Poisson-Boltzmann theory. The results show that the excess entropy is negative with its absolute value increasing for 1:1 electrolytes with increasing concentration. The symmetric Poisson-Boltzmann values are slightly overestimated, while the modified Poisson-Boltzmann values are slightly underestimated relative to the simulations. The curves for 1:1 electrolytes including that from the Laird-Haymet equations are consistent with each other, while only the MPB curves for 2:2 electrolytes at 4.25 × 10−10 m are qualitative relative to the simulations up to about 1 mol/dm3. The 2:2 electrolyte curves reveal a characteristic inflection and plateau. The results obtained in the low concentration range (< 0.01 mol/dm3) are consistent with the predictions of the Debye-Hückel limiting law.
symmetric and modified Poisson-Boltzmann theories
Copyright (c) 2025 Stanislaw Lamperski, L. B. Bhuiyan, Christopher W. Outhwaite, Rafal Gorniak https://creativecommons.org/licenses/by/4.0
Advances of Mayer's cluster approach in quantitative theoretical description of phase transitions for various lattice models of matter
Resent achievements in Statistical Theory, namely, a possibility to reproduce almost unlimited Mayer's activity series based on the information about their convergence radius, on the one hand, and generalization of the Lattice Statistics by eliminating the simplification of nearest-neighbor interactions, on the other hand, have allowed accurate quantitative description of the condensation in lattice gases, spontaneous magnetization in ferromagnets, and spinodal decomposition in binary mixtures by evaluating only a several irreducible cluster integrals (virial coefficients). In particular, the results of calculations indicate qualitative and even quantitative universality in the behavior of the mentioned lattice systems of different geometry and dimensionality at the same values of a certain reduced temperature when that behavior is expressed in terms of some dimensionless parameters. An additional possibility to describe the order-disorder phase transitions in some other lattice systems (e.g., antiferromagnets and alloys) is also discussed in the paper.
Copyright (c) 2025 M. Ushcats, L. Bulavin, S. Ushcats, Z. Burunina, O. Maiboroda, N. Romanchuk, N. Shapoval https://creativecommons.org/licenses/by/4.0
On the temperature, pressure and composition effects in the properties of water-methanol mixtures. I. Density, excess mixing volume and enthalpy, and self-diffusion coefficients from molecular dynamics simulations
We report the temperature, pressure and composition dependence of some basic properties of model liquid water-methanol mixtures. For this purpose the isobaric-isothermal molecular dynamics computer simulations are employed. Our principal focus is on the united atom non-polarizable UAM-I-EW model for methanol which was recently parametrized the paper by Garcia-Melgarejo et al. [ J. Mol. Liq., 2021, 323, 114576], combined with the TIP4P/ε water model. In perspective, the methanol model permits a convenient extension for other monohydric alcohols mixed with water. The behavior of density, excess mixing volume and enthalpy are described. Partial mixing properties are interpreted. Besides, we explored the trends of behavior of self-diffusion coefficients of the species of a mixture. The quality of predictions of the model is critically evaluated by detailed comparisons with experimental results. Various results are novel and provide new insights into the behavior of the mixtures in question at different temperatues and at high pressures. An improvement of the modelling necessary for further research is discussed.
Copyright (c) 2025 M. Cruz Sanchez, V. Trejos Montoya, O. Pizio https://creativecommons.org/licenses/by/4.0
Scaling properties of diblock copolymers: dynamic simulations study
The influence of monomer-monomer interactions on the scaling exponents and shape characteristics of a single polymer chain in a selective solvent is investigated using Langevin dynamics simulations. By systematically increasing the temperature of the solution, the effects of interactions between blocks on the conformational properties of the chain are explored. The results demonstrate that longer-range interactions cause a transition of a polymer similar to the transition for homopolymers; short-range repulsive interactions between different blocks have a negligible impact on the effective scaling exponents: they are the same regardless of the blocks being globule and coil or ideal and swollen coils.
Copyright (c) 2025 K. Haydukivska https://creativecommons.org/licenses/by/4.0
Effect of variable relative permittivity on the thermodynamics of asymmetric valency aqueous salts
Experimentally determined empirical formulae for the concentration dependent relative permittivity of aqueous solutions of MgCl2 and NiCl2 are utilized to calculate the osmotic coefficient and the mean activity coefficient of these salts for a range of concentrations. The systems are modelled using the primitive model of electrolytes and analyzed using the symmetric Poisson-Boltzmann theory, the modified Poisson-Boltzmann theory, the mean spherical approximation, and the Monte Carlo simulations. Generally, the mean spherical approximation and the modified Poisson-Boltzmann theory reproduce the benchmark simulation data well up to ∼1.6 mol/dm3 or more in many instances, while the symmetric Poisson-Boltzmann results show discrepancies starting from ∼0.25 mol/dm3. Both the simulations and the theories tend to deviate from the corresponding experimental results beyond ∼1 mol/kg.
Copyright (c) 2025 Adriel O. Quinones Rivera, Zareen Abbas, Christopher W. Outhwaite, L. B. Bhuiyan https://creativecommons.org/licenses/by/4.0
Theoretical study of thermoelectric properties of CeIr4P12 filled skutterudite for energy conversion
The structural, elastic, thermodynamic and thermoelectric characteristics of the CeIr4P12 skutterudite have been predicted for the first time by applying density functional theory and the semi-classical Boltzmann simulations. Firstly, the structural-magnetic stability was verified through ground-state energy calculations obtained from structural optimizations. The predicted single-crystal elastic constants (Cij) show that the title compound is mechanically stable. At the same time, it turns out to be dynamically stable where all the calculated phonon frequencies have positive values. The cohesive energy was calculated to verify the energy stability of the material considered. We also determined the variations of some macroscopic physical parameters as functions of temperature, namely the thermal expansion coefficient, the lattice thermal conductivity. Furthermore, we investigated the temperature dependencies of some thermoelectric coefficients such as electronic thermal conductivity, and figure of merit. Such encouraging results indicate that the compound is a potential candidate for thermoelectric devices.
Copyright (c) 2025 M. Bouchenaki, L. I. Karaouzène, B. N. Brahmi, M. Kaid Slimane https://creativecommons.org/licenses/by/4.0