Zhao Li-Zhen, Lu Wen-Cai, Qin Wei, Wang C Z, Ho K M
State Key Laboratory of Theoretical and Computational Chemistry, Institute of Theoretical Chemistry, Jilin University, Changchun, Jilin 130021, People's Republic of China.
J Phys Chem A. 2008 Jul 3;112(26):5815-23. doi: 10.1021/jp710937m. Epub 2008 Jun 6.
We performed an unbiased search for low-energy structures of medium-sized neutral Si n and Ge n clusters ( n = 25-33) using a genetic algorithm (GA) coupled with tight-binding interatomic potentials. Structural candidates obtained from our GA search were further optimized by first-principles calculations using density functional theory (DFT). Our approach reproduces well the lowest-energy structures of Si n and Ge n clusters of n = 25-29 compared to previous studies, showing the accuracy and reliability of our approach. In the present study, we pay more attention to determine low-lying isomers of Si n and Ge n ( n = 29-33) and study the growth patterns of these clusters. The B3LYP calculations suggest that the growth pattern of Si n ( n = 25-33) clusters undergoes a transition from prolate to cage at n = 31, while this transition appears at n = 26 from the PBE-calculated results. In the size range of 25-33, the corresponding Ge n clusters hold the prolate growth pattern. The relative stabilities and different structural motifs of Si n and Ge n ( n = 25-33) clusters were studied, and the changes of small cluster structures, when acting as building blocks of large clusters, were also discussed.
我们使用遗传算法（GA）结合紧束缚原子间势，对中等尺寸中性Siₙ和Geₙ团簇（n = 25 - 33）的低能量结构进行了无偏搜索。通过遗传算法搜索获得的结构候选物，进一步采用密度泛函理论（DFT）进行第一性原理计算优化。与先前的研究相比，我们的方法能够很好地重现n = 25 - 29的Siₙ和Geₙ团簇的最低能量结构，显示了我们方法的准确性和可靠性。在本研究中，我们更关注确定Siₙ和Geₙ（n = 29 - 33）的低能异构体，并研究这些团簇的生长模式。B3LYP计算表明，Siₙ（n = 25 - 33）团簇的生长模式在n = 31时从长椭球形转变为笼形，而从PBE计算结果来看，这种转变出现在n = 26时。在25 - 33的尺寸范围内，相应的Geₙ团簇保持长椭球形生长模式。研究了Siₙ和Geₙ（n = 25 - 33）团簇的相对稳定性和不同结构基序，还讨论了小团簇结构作为大团簇构建单元时的变化。
