A. V. Myshlyavtsev

Devil’s staircase behavior of a dimer adsorption model

We have constructed the simple two-dimensional adsorption model with short range non-competing interactions which demonstrates devil’s staircase of phase transitions. The main factor which leads to the appearance of infinite amount of ordered structures in our model is two competing forms of adsorption. The ground state properties of the model have been analyzed.

Monte Carlo study of adsorption of additive gas mixture

AbstractThe monolayer adsorption of binary gas mixture on a square lattice has been investigated through grand canonical Monte Carlo method and transfer matrix technique. Repulsive and attractive lateral interactions have been introduced between the adsorbed particles for one component of the gas mixture and for another, respectively, at the same time the particles of different components of the gas mixture have not interacted. The model has been studied in the ground state and at finite temperatures. Interesting features of the phase behavior of the gas mixture adlayer were observed and discussed. The model shows that a simultaneous increasing of the chemical potentials of both gas components can lead to displacing of particles of one component on the surfaces by particles of another component.

Generalized lattice-gas model for adsorption of functional organic molecules in terms of pair directional interactions.

A generalized lattice-gas model that takes into account the directional character of pair interactions between the lattice sites is proposed. It is demonstrated that the proposed model can be successfully used to deeply understand the self-assembly process in adsorption monolayers of functional organic molecules driven by specified directional interactions between such molecules (e.g., hydrogen bonding). To illustrate the idea, representative cases of the general model with different numbers of identical functional groups in the chemical structure of the adsorbed molecule are investigated with Monte Carlo and the transfer-matrix methods. The model reveals that the phase behavior of the adsorption systems considered can be characterized as a hierarchical self-assembly process. It is predicted that in real adsorption systems of this type, the energy of hydrogen bonding sufficiently depends on the mutual orientation of the adsorbed molecules.

Adsorption thermodynamics of cross-shaped molecules with one attractive arm on random heterogeneous square lattice

Understanding the forces governing the arrangement of organic molecules on the solid surface is the key to control and creation of self-assembled organic nanostructures. In this paper we use the simple lattice gas model and grand canonical Monte Carlo method to demonstrate how the random surface heterogeneity affects both structural and thermodynamic properties of the adsorption overlayer of cross-shaped molecules with one attractive arm. The simulated results show that phase behavior of the adlayer on the random heterogeneous surface characterized by small energy difference between adsorption on the “weak” and “strong” sites and/or low concentration of the “strong” sites (0.1 and less) can be described as the hierarchical self-assembly process. On the other hand, the simulations performed for the system with large energy difference between adsorption on the “weak” and “strong” sites revealed that the stable phases appearing on the surface at coverage close to 0.5 and higher are the balance products of the “adsorbate–adsorbate” and “adsorbate–substrate” interactions.

Statistical Thermodynamics of Lattice Gas Models of Multisite Adsorption

The lattice models naturally arise in different fields of physics, chemistry and other sciences. First, it is physics of the solid state and physicochemistry of the surface. Among the many well-known lattice models the magnetic, alloys, liquid mixture, adsorption models are usually mentioned. The lattice models can be both classical and quantum. In this chapter only the classical lattice models focusing on models arising in physicochemistry of the surface will be considered. For the beginning let’s give the most common formal definition of the classical lattice model.