Monte Carlo studies of the origins of the compensation effect in a catalytic reaction

Fichthorn, Kristen A.; Weinberg, W. H.

doi:10.1021/la00059a024

Cited by 26 publications

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“…For each mechanism, 15 to 20 simulations were conducted on initially random lattices of 350 2 (vacancy mechanism) and 512 2 (precursor mechanism) sites with periodic boundary conditions. As will be discussed elsewhere [18], we ascertained that the results reported here were not influenced by finite-size effects or inadequately random numbers. Figure 1 shows the average linear dimension of a domain, (/>, as a function of UIS time U for representative results of all runs for both the vacancy and precursor mechanisms.…”

Section: (1) and (2)] To Study This Decrease We Utilized A Second Msupporting

confidence: 55%

“…Our uniform interevent step methodology proved to be extremely useful in this regard. We believe that this methodology will have many useful future applications [18] because it removes a significant impediment to the interpretation of Monte Carlo simulations. Perhaps it is finally possible to attain a unified consensus as to the universality of domain growth.…”

Section: (1) and (2)] To Study This Decrease We Utilized A Second Mmentioning

confidence: 99%

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Influence of time-dependent rates of mass transfer on the kinetics of domain growth

Fichthorn

Weinberg

1992

Phys. Rev. Lett.

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Although there is a growing consensus as to the universality of domain growth kinetics in quenched systems, discrepancies remain among theory, experiments, and simulations. We identify a major discrepancy between the three-the time dependence of mass transfer kinetics. We show that this discrepancy can be resolved in Monte Carlo simulations of domain growth. Our results strengthen the emerging consensus that systems having a nonconserved order parameter obey Lifschitz-Allen-Cahn growth kinetics in the asymptotic scaling limit.PACS numbers: 68.35.Fx, 61.70.NgGrowth and ordering processes are abundant in nature, underlying phenomena as diverse as snowflake and soot formation, crystal growth, and the evolution of the Universe. The search for universality and possible subclassifications in these apparently wide and varied phenomena is a significant fundamental problem in nonequilibrium statistical mechanics [1]. In thermally quenched systems, the development of long-range order is accomplished by the growth of ordered domains. It is becoming increasingly evident that domain growth in these systems exhibits universal behavior. That is, many systems which conserve the order parameter conform to the Lifschitz-Slyozov (LS) theory [2] of domain growth, while systems having a nonconserved order parameter generally exhibit Lifschitz-Allen-Cahn (LAC) [3] growth kinetics. Ordering kinetics in these theories are described by a power-law expression of the form (l(t)) -(At) x , where (lit)) is a characteristic length of a domain at time /, A is a proportionality factor, and x is a growth exponent. In the LAC theory, x -j, while x = y in the LS theory. Although the current understanding of domain growth has emerged with considerable controversy, these theories remain the most widely accepted descriptions of domain growth.

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Section: (1) and (2)] To Study This Decrease We Utilized A Second Msupporting

confidence: 55%

Section: (1) and (2)] To Study This Decrease We Utilized A Second Mmentioning

confidence: 99%

Influence of time-dependent rates of mass transfer on the kinetics of domain growth

Fichthorn

Weinberg

1992

Phys. Rev. Lett.

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“…The extraction of parameters from the slope and y−intercept of an Arrhenius plot has proven to be a useful and important method that allows for the empirical determination of rates [13,15], however, it has been widely accepted for some time now that the parameters E a and ν need not be constants throughout many activated processes [5,[16][17][18][19][20][21]. This leads to the observation that each point in the Constable plot indeed corresponds to a data pair of fixed values of E a,i , ln ν i , therefore, if the two phenomena are to be defined separately, this raises the question of the physicochemical significance of an observed linear correlation in a case where the IKR is not simultaneously satisfied.…”

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confidence: 99%

Breakdown of kinetic compensation effect in physical desorption

2018

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The kinetic compensation effect (KCE), observed in many fields of science, is the systematic variation in the apparent magnitudes of the Arrhenius parameters Ea, the energy of activation, and ν, the preexponential factor, as a response to perturbations. If, in a series of closely related activated processes, these parameters exhibit a strong linear correlation, it is expected that an isokinetic relation will occur, then the rates k become the same at a common compensation temperature Tc. The reality of these two phenomena continues to be debated as they have not been explicitly demonstrated and their physical origins remain poorly understood. Using kinetic Monte Carlo simulations on a model interface, we explore how site and adsorbate interactions influence the Arrhenius parameters during a typical desorption process. We find that their transient variations result in a net partial compensation, due to the variations in the prefactor not being large enough to completely offset those in Ea, both in plots that exhibit a high degree of linearity and in curved non-Arrhenius plots. In addition, the observed isokinetic relation arises due to a transition to a non-interacting regime, and not due to compensation between Ea and ln ν. We expect our results to provide a deeper insight into the microscopic events that originate compensation effects and isokinetic relations in our system, and in other fields where these effects have been reported.

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“…The use of Monte Carlo simulation for the analysis of molecular processes ocurring on solid surfaces is becoming a powerful tool for the understanding of the elementary steps and mechanism of the kinetics of heterogeneous reactions. − This is especially true for complex systems where the application of approximate analytical solutions to the kinetic equations, like the quasi-chemical approximation, , may be unpractical.…”

Section: Introductionmentioning

confidence: 99%

Monte Carlo Analysis of Hydrogen Interaction with Promoter- and Inhibitor-Modified Nickel Surfaces

et al. 1997

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Monte Carlo studies of the origins of the compensation effect in a catalytic reaction

Cited by 26 publications

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Influence of time-dependent rates of mass transfer on the kinetics of domain growth

Influence of time-dependent rates of mass transfer on the kinetics of domain growth

Breakdown of kinetic compensation effect in physical desorption

Monte Carlo Analysis of Hydrogen Interaction with Promoter- and Inhibitor-Modified Nickel Surfaces

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