摘要
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.
A many-body expansion interatomic potential obtained from bulk tin was used topredict the structures and energies of small and medium size tin clusters(Sn_2-Sn_(300)).The optimized results show that small tin clusters(Sn_2-Sn_(15))prefer to take compactstructures as their most stable configuration,all unrelated with the bulk lattice;whilemedium tin clusters,like,Sn_(47),Sn_(71),Sn_(87),and Sn_(147),are still kept in shell struc-tures which are distortions of the microcrystalline fragments of solid tin,with all theshells compressed and some shells split.The energy per-atom of these clusters in-creases steadily with the increasing of the cluster size,approaching the cohesive energyof α-tin at about Sn_(740)(extrapolated),where the most stable structure should matchthe bulk lattice except for a few percents of surface atoms.
出处
《物理化学学报》
SCIE
CAS
CSCD
北大核心
1993年第5期642-649,共8页
Acta Physico-Chimica Sinica
基金
山西省政府资助项目
关键词
锡原子簇
结构
稳定性
势能函数
Tin clusters
Structures
Stabilities
Potential energy function