Dynamical Monte Carlo simulation of surface atomic recombination

Guerra, Vasco; Loureiro, J.

doi:10.1088/0963-0252/13/1/011

Cited by 28 publications

(37 citation statements)

References 23 publications

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“…Different KMC algorithms exist to choose processes and locations at which these processes occur. This includes the so called null event method proposed in ref and later implemented for plasma‐surface systems . In null event algorithms, first a surface site is randomly selected and then, depending on the occupancy of this site, one of the available processes is executed with a probability that depends on the transition rate of this process.…”

Section: Model Formulationmentioning

confidence: 99%

“…This includes the so called null event method proposed in ref [83] and later implemented for plasma-surface systems. [74,84,85] In null event algorithms, first a surface site is randomly selected and then, depending on the occupancy of this site, one of the available processes is executed with a probability that depends on the transition rate of this process. The term ''null event'' describes the simple fact that no event at all as may be selected as a results of the Monte Carlo loop.…”

Section: Kinetic Monte Carlo Algorithmsmentioning

confidence: 99%

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Deterministic and Monte Carlo methods for simulation of plasma‐surface interactions

Marinov

Teixeira

Guerra

2016

Plasma Processes & Polymers

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Two approaches to the modeling of surface kinetics in reactive plasmas are discussed. Coarse‐grained deterministic models incorporate rate balance equations for coverages of surface active sites. They are computationally effective and can be readily coupled to reactor‐scale plasma simulations. In the kinetic Monte Carlo (KMC) approach, the time evolution of a gas‐lattice system consisting of a large number of particles is described. Although being more demanding computationally, KMC algorithms are exact, allow a straightforward description of distributions of surface reactivity and help bridging the gap between simulations on atomic and macroscopic scales. In this paper, theoretical and practical aspects of deterministic and KMC modeling of plasma‐surface interactions are discussed taking O recombination on silica as a model system.

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Section: Model Formulationmentioning

confidence: 99%

Section: Kinetic Monte Carlo Algorithmsmentioning

confidence: 99%

Deterministic and Monte Carlo methods for simulation of plasma‐surface interactions

Marinov

Teixeira

Guerra

2016

Plasma Processes & Polymers

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“…We will, therefore, not discuss KMC in detail here-the interested reader is referred to Refs. [29][30][31]35. Instead, here we will concentrate on MD because it has a much stronger foundation and can retain a first-principle character once the information on the interaction potentials is derived from ab initio approaches in cases when electronic and quantum effects are not important.…”

Section: B Theoretical Approaches For the Plasma-solid Interfacementioning

confidence: 99%

Towards an integrated modeling of the plasma-solid interface

Bönitz

Filinov

Abraham

et al. 2019

Front. Chem. Sci. Eng.

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Solids facing a plasma are a common situation in many astrophysical systems and laboratory setups. Moreover, many plasma technology applications rely on the control of the plasma-surface interaction, i.e. of the particle, momentum and energy fluxes across the plasma-solid interface. However, presently often a fundamental understanding of them is missing, so most technological applications are being developed via trial and error. The reason is that the physical processes at the interface of a low-temperature plasma and a solid are extremely complex, involving a large number of elementary processes in the plasma, in the solid as well as fluxes across the interface. An accurate theoretical treatment of these processes is very difficult due to the vastly different system properties on both sides of the interface: quantum versus classical behavior of electrons in the solid and plasma, respectively; as well as the dramatically differing electron densities, length and time scales. Moreover, often the system is far from equilibrium. In the majority of plasma simulations surface processes are either neglected or treated via phenomenological parameters such as sticking coefficients, sputter rates or secondary electron emission coefficients. However, those parameters are known only in some cases and with very limited accuracy. Similarly, while surface physics simulations have often studied the impact of single ions or neutrals, so far, the influence of a plasma medium and correlations between successive impacts have not been taken into account. Such an approach, necessarily neglects the mutual influences between plasma and solid surface and cannot have predictive power.In this paper we discuss in some detail the physical processes a the plasma-solid interface which brings us to the necessity of coupled plasma-solid simulations. We briefly summarize relevant theoretical methods from solid state and surface physics that are suitable to contribute to such an approach and identify four methods. The first are mesoscopic simulations such as kinetic Monte Carlo (KMC) and molecular dynamics (MD) that are able to treat complex processes on large scales but neglect electronic effects. The second are quantum kinetic methods based on the quantum Boltzmann equation that give access to a more accurate treatment of surface processes using simplifying models for the solid. The third approach are ab initio simulations of surface process that are based on density functional theory (DFT) and time-dependent DFT. The fourths are nonequilibrium Green functions that able to treat correlation effects in the material and at the interface. The price for the increased quality is a dramatic increase of computational effort and a restriction to short time and length scales. We conclude that, presently, none of the four methods is capable of providing a complete picture of the processes at the interface. Instead, each of them provides complementary information, and we discuss possible combinations. PACS numbers:

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“…Numerous experimental and theoretical efforts have been made in order to improve our understanding of surface catalyzed atomic recombination because of its great importance for atomic sources [8], heat shielding on reusable space vehicles [7,13,14,16] and various plasma-chemical applications [6,9]. Authors [8] point out that the surface exposed to plasma presents itself a complex kinetic system and it cannot be considered as a simple boundary condition for bulk plasma.…”

Section: Introductionmentioning

confidence: 99%

Production of molecules on a surface under plasma exposure: example of NO on pyrex

Marinov¹,

Guaitella²,

Rousseau³

et al. 2010

J. Phys. D: Appl. Phys.

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We propose a new experimental approach to the study of surface-catalyzed nitric oxide production under plasma exposure. Stable nitrogen species are grafted to the surface of pyrex discharge tube during N 2 plasma pretreatment. These species are trapped by surface active sites and being exposed to O 2 plasma, they initiate production of NO molecules, which are detected using tunable diode laser absorption spectroscopy. Supposing that nitrogen species are adsorbed N atoms, we estimate the initial surface coverage [N ads ]=3·10 13 cm -2 . That gives an assessment of the lower boundary of the surface active sites density.

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Dynamical Monte Carlo simulation of surface atomic recombination

Cited by 28 publications

References 23 publications

Deterministic and Monte Carlo methods for simulation of plasma‐surface interactions

Deterministic and Monte Carlo methods for simulation of plasma‐surface interactions

Towards an integrated modeling of the plasma-solid interface

Production of molecules on a surface under plasma exposure: example of NO on pyrex

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