Markov-chain model of classified atomistic transition states for discrete kinetic Monte Carlo simulations.
Markov-chain model of classified atomistic transition states for discrete kinetic Monte Carlo simulations.
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用于离散动力学蒙特卡罗模拟的分类原子过渡态的马尔可夫链模型。
DOI：
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发表时间：
2011
期刊：
影响因子：
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通讯作者：
Roger Smith
中科院分区：
文献类型：
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作者：
S. Numazawa;Roger Smith
将经典调和跃迁态理论应用于具有层次跃迁水平的离散晶格单元。然后使用该方案来确定可以应用于基于晶格的动力学蒙特卡罗（KMC）原子模拟模型的转换。该模型利用热激活原子扩散过程的过渡能级分类方案，有效地减少了KMC模拟步骤。热激活原子运动被认为是局部跃迁事件，在一定的局部时间内被限制在势能阱中。这些过程用三维格空间中多维布尔值函数的马尔可夫链来表示。在一定能级下被势垒抑制的事件被视为正则系综的热涨落，可以自由接受。因此，波动系统演化过程被实现为等价类对象的马尔可夫链。结果表明，该过程具有接受亚稳态局域跃迁的特征。将该方法应用于波纹表面上的金和银团簇生长问题。模拟预测了从局部亚稳态到稳定状态的形态依赖的过渡时间限制的存在，用于随后的星团通过吸积增长。所得结果与实验结果非常吻合。
Classical harmonic transition state theory is considered and applied in discrete lattice cells with hierarchical transition levels. The scheme is then used to determine transitions that can be applied in a lattice-based kinetic Monte Carlo (KMC) atomistic simulation model. The model results in an effective reduction of KMC simulation steps by utilizing a classification scheme of transition levels for thermally activated atomistic diffusion processes. Thermally activated atomistic movements are considered as local transition events constrained in potential energy wells over certain local time periods. These processes are represented by Markov chains of multidimensional Boolean valued functions in three-dimensional lattice space. The events inhibited by the barriers under a certain level are regarded as thermal fluctuations of the canonical ensemble and accepted freely. Consequently, the fluctuating system evolution process is implemented as a Markov chain of equivalence class objects. It is shown that the process can be characterized by the acceptance of metastable local transitions. The method is applied to a problem of Au and Ag cluster growth on a rippled surface. The simulation predicts the existence of a morphology-dependent transition time limit from a local metastable to stable state for subsequent cluster growth by accretion. Excellent agreement with observed experimental results is obtained.