First-principles Study Of Ground-state Structures And Electronic Properties Of Pb_nS(n=1-13) And Si_mSb (m=1-14) Clusters

In this paper, Geometric structures of Pb_nS(n=1-13) clusters and Si_mSb(m=1-14) clusters are optimized using the generalized gradient approximation(GGA) density functional theory, the magic numbers and bond binding property of Pb_nS clusters and the magic numbers Si_mSb clusters are obtained by analysing the structures and electronic properties of Pb_nS clusters and Si_mSb clusters. The main contents are presented as the followings:In Chapter 1, we introduce prieftly the basic concept of density functional theory. For example, characteristic and concept of density functional theory, i.e. Introducing concept of density functional theory, we prieftly introduce theorem of Hohenberg-Kohn and Kohn-Sham equation, which are how to prove. Furthermore, We also introduce exchange-correlation functionals, and computational methods of density functional theory, and mulliken population analysis in brief.In Chapter 2, firstly ,we introduce Materials studio software in chapter 2. secondly, we introduce Dmol~3 software. Thirdly , we introduce the theoretical meaning of study of Pb_nS clusters and Si_mSb clusters using density functional theory.In Chapter 3, we prieftly study structures and electronic properties of Pb_nS clusters and Si_mSb clusters. firstly, we systematically study the geometric structures and electronic properties of Pb_nS (n= 1-13) clusters using the generalized gradient approximation(GGA) density-functional theory (DFT), and the energy and frequency are calculated, the ground state structures of Pb_nS (n=1-13)clusters are obtained. We find that 4 and 10 are the magic numbers of Pb_nS (n=1-13)clusters by analysing average binding energy,second-order difference energy,HOMO,LUMO,HLG and VIP of Pb_nS(n=1-13)clusters. And then, analysizing the population analysis of Pb_nS (n=1-13)clusters, we find that ionic and covalent bonding are co-existence in Pb_nS clusters; secondly, we study Geometric structures and electronic properties of Si_mSb (m=1-14) clusters using the generalized gradient approximation(GGA) density functional theory. We obtained that 4,10 and 12 are the magic numbers of Si_mSb (m=1-14) clusters by analysing average binding energy,second-order difference energy,HLG andâ–³E of Si_mSb (m=1-14)clusters...