The molecular approach to heterogeneous nucleation.
The molecular approach to heterogeneous nucleation.
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DOI：
10.1063/1.1881032
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发表时间：
2005-03
期刊：
影响因子：
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通讯作者：
E. Zapadinsky;A. Lauri;M. Kulmala
中科院分区：
文献类型：
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作者：
E. Zapadinsky;A. Lauri;M. Kulmala
发展了一种非均质成核的分子方法。导出了平衡团簇分布、团簇形成的可逆功和成核速率的表达式。制定了两份单独的培训工作说明。如果将平衡团簇分布在基底表面附近的单体浓度上归一化，可逆生成功表示为Δ G（het）（I）=（F（n）（het）-F（n）（hom））-（F（1）（het）-F（1）（hom））+ Δ G（hom）其中F（n）（het）和F（n）（hom）分别是与衬底相互作用的团簇和不与衬底相互作用的团簇的亥姆霍兹自由能。如果平衡簇分布在远离基底表面的单体浓度上归一化，则簇形成的功由Δ G（het）（II）=（F（n）（het）-F（n）（hom））+ Δ G（hom）给出。前者与经典非均质形核理论的方法相一致。簇配分函数似乎取决于虚拟平面的位置，该虚拟平面将体积分开，其中簇与衬底的相互作用是有效的，而相互作用可以忽略不计。我们的Monte Carlo模拟表明，这种依赖性相当弱，因此平面的位置不是很重要。根据模拟，在20至50埃范围内的平面位置的变化不会导致异相成核速率的显著变化。
A molecular approach to heterogeneous nucleation has been developed. The expressions for the equilibrium cluster distribution, the reversible work of the cluster formation, and the nucleation rate have been derived. Two separate statements for the work of formation were formulated. If the equilibrium cluster distribution is normalized on the monomer concentration near the substrate surface, the reversible work of formation is expressed by DeltaG(het) (I) = (F(n) (het)-F(n) (hom))-(F(1) (het)-F(1) (hom)) + DeltaG(hom) where F(n) (het) and F(n) (hom) are the Helmholtz free energies of a cluster interacting with a substrate and a cluster not interacting with the substrate, respectively. If the equilibrium cluster distribution is normalized on the monomer concentration far from the substrate surface, the work of cluster formation is given by DeltaG(het) (II) = (F(n) (het)-F(n) (hom)) + DeltaG(hom). The former expression corresponds to the approach of the classical heterogeneous nucleation theory. The cluster partition function appears to be dependent on the location of a virtual plane, which separates the volume, where the interaction of the clusters with the substrate is effective from the one where interaction is negligible. Our Monte Carlo simulations have shown that the dependence is rather weak and thus the location of the plane is not very important. According to the simulations the variation of the plane position in the range from 20 to 50 Angstroms does not lead to a considerable change of the heterogeneous nucleation rate.