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Proof for an additional T2 failure time dependence of the activation energy measured using Black's equation is provided. The investigation was conducted under the condition that the activation energy should be equal to the energy barrier needed for atomic hopping. Microscopic modeling , which offers an explicit connection between the microscopic parameters and macroscopic behavior of the model, is capable of providing a reliable technique of monitoring self-diffusion activation energies in pure metals.

We explore the interplay of New Physics (NP) effects in (g− 2)ℓ and h→ℓ+ℓ− within the Standard Model Effective Field Theory (SMEFT) framework, including one-loop Renormalization Group (RG) evolution of the Wilson coefficients as well as matching to the observables below the electroweak symmetry breaking scale. We include both the leading dimension six chirality flipping operators including a Higgs and SU(2)L gauge bosons as well as four-fermion scalar and tensor operators, forming a closed operator set under the SMEFT RG equations. We compare present and future experimental sensitivity to different representative benchmark scenarios. We also consider two simple UV completions, a Two Higgs Doublet Model and a single scalar LeptoQuark extension of the SM, and show how tree level matching to SMEFT followed by the one-loop RG evolution down to the electroweak scale can reproduce with high accuracy the (g−2)ℓ and h→ℓ+ℓ− contributions obtained by the complete one- and even two-loop calculations in the full models. [ABSTRACT FROM AUTHOR]

A study was conducted to analyze a microscopic nucleation model for electromigration on a lattice. The solution of the master equations for site occupancy generates a variable current exponent with 1

During CO-oxidation on Pt(100), CO diffuses in a ‘‘disordered environment’’ produced by a complex pattern of reconstructed and unreconstructed regions of the substrate. Macroscopic diffusion of CO is effectively only possible on percolating 1×1-regions of the substrate. We treat the spatio-temporal behavior observed in this reaction system accounting in the simple way for the percolative nature of CO-diffusion. This is done via incorporation into the reaction-diffusion equations of a suitable chemical diffusion coefficient, exploiting ideas from the theory of transport in disordered media. We use these equations to analyze the propagation of reactive, O-rich pulses into a CO-covered 1×1-background. © 1996 American Institute of Physics. [ABSTRACT FROM AUTHOR]

For surface reactions on single-crystal substrates which involve highly mobile adspecies, there is a vast separation in natural time and length scales. Adspecies hop rates can be many orders of magnitude larger than rates for other processes. Strong spatial correlations or ordering can exist on the atomic scale, while spatial pattern formation occurs on a macroscopic scale due to high diffusivity. An efficient analysis of such systems is provided by a ‘‘hybrid treatment’’ which we apply here to the monomer–dimer surface reaction model in the case of coexisting immobile dimer adspecies and highly mobile monomer adspecies. Specifically, we combine a mean-field treatment of the ‘‘randomized’’ mobile adspecies, and a lattice-gas description of the immobile adspecies. Monte Carlo simulations then reveal bistability and ‘‘critical’’ bifurcation phenomena, while precisely accounting for the influence of correlations in the immobile adspecies distribution. A corresponding analysis of the evolution of macroscopic spatial inhomogeneities is achieved through parallel simulation of the distributed macroscopic points with distinct correlated states and adspecies coverages. These simulations are appropriately coupled to describe diffusive mass transport of the mobile adspecies. In this way, we examine for this model the propagation and structure of chemical waves, corresponding to interface between bistable reactive states, and thereby determine the relative stability of these states. © 1995 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Presents a developed lattice-gas model to describe reactive removal of a preadsorbed, mixed nitrogen oxide + carbon monoxide adlayer covering a platinum(100) surface. Analysis of lattice-gas model behavior; Removal of the adlayer; Provision of rate equation formulation for the initial disperse stage; Development of chemical diffusion treatment.

Analyzes chemical wave propagation in a lattice-gas model for carbon monoxide-oxidation with varying degrees of carbon monoxide-mobility. Role of hydrodynamic reaction-diffusion equation in the carbon monoxide-mobility propagation; Effect of oxygen coverage on the chemical diffusivity of carbon monoxide; Details on the hybrid approach.

Atomistic lattice-gas models for surface reactions can accurately describe spatial correlations and ordering in chemisorbed layers due to adspecies interactions or due to limited mobility of some adspecies. The primary challenge in such modeling is to describe spatiotemporal behavior in the physically relevant "hydrodynamic" regime of rapid diffusion of (at least some) reactant adspecies. For such models, we discuss the development of exact reaction-diffusion equations (RDEs) describing mesoscale spatial pattern formation in surface reactions. Formulation and implementation of these RDEs requires detailed analysis of chemical diffusion in mixed reactant adlayers, as well as development of novel hybrid and parallel simulation techniques. [ABSTRACT FROM AUTHOR]