Melting and evaporation transitions in small Al clusters: canonical Monte-Carlo simulations
Melting and evaporation transitions in small Al clusters: canonical Monte-Carlo simulations
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DOI：
10.1140/epjb/e2005-00026-6
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发表时间：
2004-12
期刊：
影响因子：
--
通讯作者：
Ralph Werner
中科院分区：
文献类型：
--
作者：
Ralph Werner
由束缚原子组成的二聚体不能熔化，只能解离。大块金属在固相和液相之间表现出明确的一级转变。利用Gupta势模拟的Al簇的蒙特卡罗模拟，通过比热和键长δB （Berry参数）的均方根的特征，探讨了增加簇尺寸的熔化转变的出现。N ~ 6原子出现了明显的熔化跃迁特征。闭合壳层效应在56个原子的团簇中表现出来。将熔融转变与解离转变进行了详细的比较，解离转变在较高温度下会引起比热的第二个可能更大的局部最大值。较大的团簇会分裂成二聚体和三聚体，而二聚体又会在较高的温度下解离。
A dimer of bound atoms cannot melt, only dissociate. Bulk metals show a well defined first order transition between their solid and liquid phases. The appearance of the melting transition is explored for increasing clusters sizes via the signatures in the specific heat and the root mean square of the bond lengths δB (Berry parameter) by means of Monte-Carlo simulations of Al clusters modelled by Gupta potentials. Clear signatures of a melting transition appear for N∼6 atoms. Closed-shell effects are shown for clusters with up to 56 atoms. The melting transition is compared in detail with the dissociation transition, which induces a second and possibly much larger local maximum in the specific heat at higher temperatures. Larger clusters are shown to fragment into dimers and trimers, which in turn dissociate at higher temperatures.