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The kinetic Monte Carlo method as a way to solve the master equation for interstellar grain chemistry.

Cuppen HM, Karssemeijer LJ, Lamberts T - Chem. Rev. (2013)

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Affiliation: Theoretical Chemistry, Institute for Molecules and Materials, Radboud University Nijmegen , 6525 AJ Nijmegen, The Netherlands.

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number on the grain considered never exceeded five... The resulting the steady-state recombination efficiency24where NH is the number of arriving H atoms and NH2 is the number of formed H2 molecules adsorption... Fractions lower than 1 effectively decrease the flux of behavior of H2 from graphite, testing the KMC simulations by an exponential function and reaches steady state... Swapping results Rate equation results were compared with microscopic KMC results... reactions leading to species such as H2 and H2O are found to dominate; for higher temperatures (T = 30 K) oxygenation starts to take over, leading to the formation becomes even worse and lattice-based KMC simulations of these systems The adaptive kinetic Monte Carlo method is an on-the-fly, off-lattice, KMC method is sufficient confidence that all low-lying saddle points have been found.

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Schematic representation of the honeycomb lattice of a graphenelayer with a hydrogen atom attached (gray circle). Stable dimer configurationscan be formed by attachment of a second hydrogen atom at the o(rtho)or p(ara) position.
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fig13: Schematic representation of the honeycomb lattice of a graphenelayer with a hydrogen atom attached (gray circle). Stable dimer configurationscan be formed by attachment of a second hydrogen atom at the o(rtho)or p(ara) position.

Mentions: The formation of themost abundant molecule in the universe, H2, occurs mainlythrough surface reactions, and as such it has received considerableattention. These reactions have been the topic of several astrochemicalmodeling studies as mentioned in previous sections, but also of experimentsand quantum chemical calculations. A model system for H2 formation on carbonaceous grains is the deposition of H atoms ona graphite surface or a graphene layer. Figure 13 shows a schematic representation of the honeycomb lattice of a graphenelayer. Hydrogen atoms can be chemically attached to the carbon atomsin this hexagonal lattice. The gray circle represents such an atom.Molecular hydrogen can be formed by a process called “abstraction”,where the atom chemisorbed to the surface reacts with another H atomto form H2. Hydrogen abstraction from graphite has beenstudied extensively both experimentally103,104 and by density functional theory (DFT) and quantum wave packet calculations.105−110


The kinetic Monte Carlo method as a way to solve the master equation for interstellar grain chemistry.

Cuppen HM, Karssemeijer LJ, Lamberts T - Chem. Rev. (2013)

Schematic representation of the honeycomb lattice of a graphenelayer with a hydrogen atom attached (gray circle). Stable dimer configurationscan be formed by attachment of a second hydrogen atom at the o(rtho)or p(ara) position.
© Copyright Policy
Related In: Results  -  Collection

License
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getmorefigures.php?uid=PMC3934372&req=5

fig13: Schematic representation of the honeycomb lattice of a graphenelayer with a hydrogen atom attached (gray circle). Stable dimer configurationscan be formed by attachment of a second hydrogen atom at the o(rtho)or p(ara) position.
Mentions: The formation of themost abundant molecule in the universe, H2, occurs mainlythrough surface reactions, and as such it has received considerableattention. These reactions have been the topic of several astrochemicalmodeling studies as mentioned in previous sections, but also of experimentsand quantum chemical calculations. A model system for H2 formation on carbonaceous grains is the deposition of H atoms ona graphite surface or a graphene layer. Figure 13 shows a schematic representation of the honeycomb lattice of a graphenelayer. Hydrogen atoms can be chemically attached to the carbon atomsin this hexagonal lattice. The gray circle represents such an atom.Molecular hydrogen can be formed by a process called “abstraction”,where the atom chemisorbed to the surface reacts with another H atomto form H2. Hydrogen abstraction from graphite has beenstudied extensively both experimentally103,104 and by density functional theory (DFT) and quantum wave packet calculations.105−110

View Article: PubMed Central - PubMed

Affiliation: Theoretical Chemistry, Institute for Molecules and Materials, Radboud University Nijmegen , 6525 AJ Nijmegen, The Netherlands.

AUTOMATICALLY GENERATED EXCERPT
Please rate it.

number on the grain considered never exceeded five... The resulting the steady-state recombination efficiency24where NH is the number of arriving H atoms and NH2 is the number of formed H2 molecules adsorption... Fractions lower than 1 effectively decrease the flux of behavior of H2 from graphite, testing the KMC simulations by an exponential function and reaches steady state... Swapping results Rate equation results were compared with microscopic KMC results... reactions leading to species such as H2 and H2O are found to dominate; for higher temperatures (T = 30 K) oxygenation starts to take over, leading to the formation becomes even worse and lattice-based KMC simulations of these systems The adaptive kinetic Monte Carlo method is an on-the-fly, off-lattice, KMC method is sufficient confidence that all low-lying saddle points have been found.

No MeSH data available.