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基于从固体锡确立的多体展开势能函数,采用座标直接优化方法预测了锡原子簇分子(Sn_2-Sn_(?))的结构和相对稳定性,并用蒙特卡罗方法验证了有关小的原子簇(Sn_2-Sn_(15))的所有结果.优化结果表明:(1)小的锡原子簇分子(Sn_2-Sn_(15))倾向于密堆积结构,与锡晶体结构无关;(2)中等大小的簇分子,如Sn_(47),Sn_(?)Sn_(?)及Sn_(147)等,则呈α-Sn 晶体的畸变结构,其外围各层原子到中心原子的距离受到压缩,且某些层被劈裂为两层或多层;(3)随着原子簇尺寸的进一步增大,结构畸变逐渐减弱,簇分子的单原子平均结合能缓慢增大,其外椎值大约在Sn_(740)处趋近于α-Sn 的结合能.
The structure and relative stability of tin cluster molecules (Sn_2-Sn_ (?)) Were predicted by the coordinate direct optimization method based on the multi-body expansion potential function established from solid tin. Monte-Carlo method was used to verify the dependence of small atoms (Sn_2-Sn_ (15)). The results of the optimization show that: (1) the small tin cluster molecules (Sn_2-Sn_ (15)) tend to be close packed structure and have nothing to do with the tin crystal structure; (47), Sn (?) Sn_ (?) And Sn_ (147) are the distorted structures of α-Sn crystal, the distance between the atoms in the outer layers and the central atom is reduced, and Some layers are split into two or more layers. (3) With the further increase of cluster size, the structural distortion gradually weakened and the average binding energy of cluster molecules slowly increases. (740) approaches the alpha-Sn binding energy.