利用密度泛函理论对Si_2B_nN_(n+2)^(0±)(1≤n≤4)团簇结构及性质的研究  

The structures and properties of Si_2B_nN_(n+2)^(0±)( 1≤n≤4) clusers have been studied by using density-functional theory

作　　者：田春山[1] 

机构地区：[1]青海大学基础部,青海西宁810016

出　　处：《青海大学学报（自然科学版）》2017年第3期93-98,共6页Journal of Qinghai University(Natural Science)

基　　金：教育部春晖计划项目(Z2014003)

摘　　要：由于Si与BN晶体有着特殊的物化性质,对Si BN三元掺杂团簇结构、性质的研究及功能材料的研发有着重要的意义。文中采用密度泛函理论中的B3LYP/6-31G(D)方法,对Si_2B_nN_(n+2)^(0±)(1≤n≤4)团簇所有可能构型进行了全面优化,得到相应基态结构,进一步研究了团簇对称性、电子态、平均结合能、能隙(HOMO-LUMO)、键角N-Si-N和N-B-N。结果表明:团簇Si_2B_nN_(n+2)^(0±)基态均为平面单环或近似平面单环结构,平均结合能随n均单调递增;正离子团簇相比中性团簇能隙均增加,化学稳定性增强,当n=2时能隙增加最大,值为12.969 ev;Si_2B_nN_(n+2)^(0±)(1≤n≤4),Si,B,N平均自然电荷分别为1.053,0.718,-0.858 e,Si_2B_nN_(n+2)^(+)(1≤n≤4),Si,B,N平均自然电荷分别为0.920,0.487,-0.457 e,Si_2B_nN_(n+2)^(-)(1≤n≤4),Si,B,N平均自然电荷分别为0.294,0.247,-0.491 e。全面优化获得(BN)n团簇在结构、对称性、能量等方面与已有研究的(BN)n团簇符合的较好,说明计算是可靠的。Based on specific physic-chemical properties of Si and BN crystals,Si BN ternary study on structures and properties of doped clusters and has important significance in the research and development of functional materials. All possible configuration and relative stabilities of Si2BnN( 0 ±)n + 2( 1≤n≤4) cluster are studied by the density functional theory( B3LYP) with 6-31G( D) basis sets. and get the Ground state structure,so that its symmetry and electronic State,average binding energy,the energy gap( HOMO-LUMO),the angles N-Si-N and N-B-N for further study.Results show that cluster Si_2B_nN_(n+2)^(O) the Ground state structure for planar ring or nearly planar ring structure. average binding energy with n are monotonically increasing; Si_2B_nN_(n+2)^(0±)( 1≤n≤4)compared with the corresponding neutral cluster energy gap increase,enhanced chemical stability.n = 2 the gaps increase the maximum,a value of 12. 969 ev; Si_2B_nN_(n+2)^(0 ±)( 1≤n≤4),Si,B and N average natural charge respectively for 1. 053,and 0. 718,and-0. 858 e,Si_2B_nN_(n+2)^(0±)( 1≤n≤4),Si,B and N average natural charge respectively for 0. 920,0. 487 and-0. 457 e,Si2BnN( 0 ±)n + 2( 1≤n≤4),Si,B and N average natural charge respectively for 0. 294,0. 247 and-0. 491 e.Comprehensive optimization for( BN)nclusters in such aspects as structure,symmetry,energy and the existing( BN)nclusters comform to good,that calculation is reliable.

关 键 词：Si2BnNn+2^(0±)(1≤n≤4)团簇 电子态 平均结合能 能隙 

分 类 号：O561.2[理学—原子与分子物理]