Evidence for the formation of two types of oxygen interstitials in neutron-irradiated α-AlO single crystals.

Due to unique optical/mechanical properties and significant resistance to harsh radiation environments, corundum (α-AlO) is considered as a promising candidate material for windows and diagnostics in forthcoming fusion reactors. However, its properties are affected by radiation-induced (predominantly, by fast neutrons) structural defects. In this paper, we analyze thermal stability and recombination kinetics of primary Frenkel defects in anion sublattice - the F-type electronic centers and complementary oxygen interstitials in fast-neutron-irradiated corundum single crystals.

Distinctive features of diffusion-controlled radiation defect recombination in stoichiometric magnesium aluminate spinel single crystals and transparent polycrystalline ceramics.

MgAlO spinel is important optical material for harsh radiation environment and other important applications. The kinetics of thermal annealing of the basic electron (F, F) and hole (V) centers in stoichiometric MgAlO spinel irradiated by fast neutrons and protons is analyzed in terms of diffusion-controlled bimolecular reactions. Properties of MgAlO single crystals and optical polycrystalline ceramics are compared.

Static and dynamic screening effects in the electrostatic self-assembly of nano-particles.

In the description of charge screening in the electrostatic self-assembly of nanoparticles (molecules) embedded into a polar solvent, the static screening effects (a contribution associated with the rapid spatial redistribution of small and highly mobile ions of a solvent) are traditionally treated phenomenologically, using the Yukawa short-range potential for describing the interaction between these particles. However, this model has a limited range of applicability being valid only for infinitely diluted systems and high salt concentrations. During a slow self-assembling process with nanoparticle formation, very dense structural elements (aggregates) are formed, in which the distances between the nanoparticles could become comparable to the Debye radius in the Yukawa potential.

Theory of non-equilibrium critical phenomena in three-dimensional condensed systems of charged mobile nanoparticles.

A study of 3d electrostatic self-assembly (SA) in systems of charged nanoparticles (NPs) is one of the most difficult theoretical problems. In particular, the limiting case of negligible or very low polar media (e.g.

Atomistic theory of mesoscopic pattern formation induced by bimolecular surface reactions between oppositely charged molecules.

The kinetics of mesoscopic pattern formation is studied for a reversible A+B⇌0 reaction between mobile oppositely charged molecules at the interface. Using formalism of the joint correlation functions, non-equilibrium charge screening and reverse Monte Carlo methods, it is shown that labyrinth-like percolation structure induced by (even moderate-rate) reaction is principally non-steady-state one and is associated with permanently growing segregation of dissimilar reactants and aggregation of similar reactants into mesoscopic size domains. A role of short-range and long-range reactant interactions in pattern formation is discussed.

Pattern formation kinetics for charged molecules on surfaces: microscopic correlation function analysis.

The kinetics of pattern formation and phase separation in a system of two types of oppositely charged molecules with competing short- and long-range interactions on surfaces/interfaces is studied combining three methods: a microscopic formalism of the joint correlation functions, reverse Monte Carlo, and nonequilibrium charge-screening factors. The molecular ordering occurs on the background of the Ostwald ripening and thus is strongly nonequilibrium. We have demonstrated how initial random distribution of molecules is changed for loose similar-molecule aggregates, with further reorganization into dense macroscopic domains of oppositely charged molecules.

The non-equilibrium charge screening effects in diffusion-driven systems with pattern formation.

The effects of non-equilibrium charge screening in mixtures of oppositely charged interacting molecules on surfaces are analyzed in a closed system. The dynamics of charge screening and the strong deviation from the standard Debye-Hückel theory are demonstrated via a new formalism based on computing radial distribution functions suited for analyzing both short-range and long-range spacial ordering effects. At long distances the inhomogeneous molecular distribution is limited by diffusion, whereas at short distances (of the order of several coordination spheres) by a balance of short-range (Lennard-Jones) and long-range (Coulomb) interactions.

Microscopic approach to the kinetics of pattern formation of charged molecules on surfaces.

A microscopic formalism based on computing many-particle densities is applied to the analysis of the diffusion-controlled kinetics of pattern formation in oppositely charged molecules on surfaces or adsorbed at interfaces with competing long-range Coulomb and short-range Lennard-Jones interactions. Particular attention is paid to the proper molecular treatment of energetic interactions driving pattern formation in inhomogeneous systems. The reverse Monte Carlo method is used to visualize the spatial molecular distribution based on the calculated radial distribution functions (joint correlation functions).

Synchronization of surface reactions via Turing-like structures.

We discuss an alternative to the traditional gas-phase coupling approach in order to explain synchronized global oscillations in CO oxidation on Pt(110). We use a microscopic model which includes structural Pt surface reconstruction via front propagation, and large diffusion rates for CO. The synchronization mechanism is associated with the formation of a Turing-like structure of the substrate.

Internal spatiotemporal stochastic resonance in the presence of weak noise.

We show the existence of internal stochastic resonance in a microscopic stochastic model for the oscillating A+1 / 2B(2) reaction on a square lattice. This stochastic resonance arises directly from the elementary reaction steps of the system without any external input. The lattice gas model is investigated by means of Monte Carlo simulations.

Kinetic model for surface reconstruction.

A microscopic kinetic model for the alpha <==> beta [e.g., hex <==> 1x1 for Pt(100) and 1x2 <==> 1x1 for Pt(110)] surface reconstruction is investigated by means of the mean field approximation and Monte Carlo simulations.

Model of the catalytic A+B-->0 reaction with surface reconstruction.

The A+B-->0 reaction model with a surface reconstruction is analyzed. It is compared with another similar model for the A+1/2B2-->0 reaction [V. N.

Reply to "comment on 'Monte Carlo simulations for a Lotka-type model with reactant surface diffusion and interactions' ".

We reply to the Comment by Zhdanov [preceding paper, Phys. Rev. E 65, blacksquare, square, filled (2002)] on our recent paper [G.

Global oscillation mechanism in the stochastic Lotka model.

The microscopic one-parameter kinetic model of the oscillatory A+B-->2 B reaction (Lotka model) is studied using direct Monte Carlo simulations and analytical methods. Percolation is proposed as the mechanism of global oscillations that are not limited to any finite size of a system. An analytical estimate of the oscillation frequency is derived and compared to computer simulations.

Monte Carlo simulations for a Lotka-type model with reactant surface diffusion and interactions.

The standard Lotka-type model, which was introduced for the first time by Mai et al. [J. Phys.

Comment on "surface restructuring, kinetic oscillations, and chaos in heterogeneous catalytic reactions".

In a recent article Zhdanov studied the oscillating NO+H2 reaction on the Pt(100) single-crystal surface [V. P. Zhdanov, Phys.

Monte carlo simulations of the periodically forced autocatalytic A+B-->2B reaction.

The one-parameter autocatalytic Lotka-like model, which exhibits self-organized oscillations, is considered on a two-dimensional lattice, using Monte Carlo computer simulations. Despite the simplicity of the model, periodic modulation of the only control parameter drives the system through a sequence of frequency locking, quasiperiodic, and resonance behavior.