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.

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.

A model of the non-concentric spherical core–shell quantum dot under the influence of an externally applied electric field was proposed. It was established that the energy spectrum of both the electron and the hole depends on the intensity of the electric field as well as on the specific location of the core within the quantum dot. The phenomenon of energy level splitting and degeneration was analyzed in detail. Additionally, the variations in the optical gap were determined and expressed as a function of the applied electric field strength and the position of the core in the quantum dot.

In this paper, we studied the structural and electronic properties of MoSe2 monolayer in its pure and doped forms, using the density functional theory (DFT), and the calculations were performed using Quantum Espresso (QE) software package. The doped systems are a MoSe2 monolayer with a vacancy in Mo site (Mo vacancy system), the MoSe2 monolayer with an As atom as substitutional for Mo atom (As(Mo) doped system) and an MoSe2 monolayer with As atom in an interstitial site in the hollow location of the center of one ring of the structure between the plane Mo atoms and the plane containing Se atoms (As interstitial system). We calculated the formation energy of various structures studied in Se-rich condition. We found that the As(Mo) doped system is a favorable configuration, whereas the As interstitial system is metastable. Different defects introduce midgap levels, which were interpreted according to the orbitals involved in their formation using the analysis of the band structure and DOS and PDOS of each system. The energy gap increases in all system structures and its value ranged between 1.5 eV and 1.73 eV, the Fermi level shifts toward the valence band for the Mo vacancy system, and As(Mo) doped system which suggests that it can be a p-type semiconductor, whereas Fermi level shifts to the conduction band for As interstitial system and suggests a n-type semiconductor behavior. The obtained results enable us to predict the possibility of using these systems in many applications, since it can be used in the As(Mo) doped system in photocatalysis or in photovoltaic applications in the visible light, and As interstitial system can be used in electronics applications in the infrared field.

We discuss the distribution of partition function zeros for the grand-canonical ensemble of the zeta-urn model, where tuning a single parameter can give a first or any higher order condensation transition. We compute the locus of zeros for finite-size systems and test scaling relations describing the accumulation of zeros near the critical point against theoretical predictions for both the first and higher order transition regimes.

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.

We analyze the universal conformational properties of complex copolymer macromolecules, based on two topologies: the rosette structure containing fc linear branches and fr closed loops grafted to the central core, and the symmetric pom-pom structure, consisting of a backbone linear chain terminated by two branching points with functionalities f. We assume that the constituent strands (branches) of these structures can be of two different chemical species a and b. 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.

The appearance of spontaneous polarization in CuInP2S6 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 s = 1/2 and S = 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 CuInP2S6 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 TC.

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.

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.