A Density Functional Investigation Of Nickel Doped Silicon Cluster

The property of cluster-assemble material not only relates to the size of its building block, but rely on the accurate atomic and electronic configuration of clusters. Therefore, a considerable number of group have exert themselves at all kinds of methods to explore the stable structures and electronic configurations of clusters, both theoretically and experimentally. Due to their technological importance in semiconductor fabrication and new material design research, in particular, transition metal silicides (in particular NiSi2) constitute prototype systems in surface science studies for understanding the effect of the transition metal atoms in surface reconstruction and hetero-diffusion, these technically important clusters have attracted extensive attentions.In the first chapter of this paper, we introduced briefly the new improvement of carbon clusters and silicon clusters, summarized the computational quantum chemistry method witch relate to cluster-assemble-material design. The second chapter runs back over on the groundwork of theoretical computation-quantum mechanics theory (ab initio).In the third and the fourth chapter, NiSin (n=1-6) and Ni2Sin (n=l-6) clusters are investigated systemically using hybrid-density-functional theory. Geometry optimizations and electronic population analyses are performed for NiSin(n=1-6) and Ni2Sin(n=1-6) clusters at the (U)B3LYP level employing LanL2DZ basis sets. The ground state of NiSin(n=1-6) and Ni2Sip(n=l-6) clusters arc identified, with Mulliken atomic net population and overlap population, nature population, nature electronic configuration calculated and listed. The calculation result turns up that the fragmentation energies D(2,l)of NiSin(n=1-6) and Ni2Sin(n=1-6)clusters is the largest one, which defined as the energy differences upon removal of one Si atom from most stable NiSin(n=2-6) or Ni2Sin(n=2-6)clusters. This result indicate that the NiSi2 and Ni2Si2 with spin triple configuration are the most stable structure among NiSin(n=1-6) and Ni2Sin(n=1-6)clusters, respectively. The calculation results also indicate that the 3d sub shell of Ni atoms trend to obtain more electrons, but on the whole, electrons is bereaved from Ni atoms. On the other hand, in the ground state of NiSin(n=1-6) andNi2Sin(n=1-6) clusters, electronic charges is transferred from Si-Si bond to Ni-Si bond, forming Ni-Si covalent bond, and the Mulliken overlap population of Ni-Si is positive, which I'orming bonding orbital and contribute to the stability of clusters. In addition, in the fourth chapter, the spin population of Ni atoms in most stable Ni2Sin(n=1-6)clusters are listed out, this result indicate that me magnet contribution of Ni atoms in Ni2Sin(n=1-6)clusters is increase as the spin multiples from S=1 to S=5.The fifth chapter, the theoretical simulation calculation of consequence and its active effects, along with current quandary, chances and challenges, in filed of cluster and nanometer-material design, are presented. Prospect and expectations is set forward for the recent future.