摘要
使用密度泛函理论(DFT)的杂化密度泛函B3LYP方法在6-31G*基组水平上对SimCn(m+n≤7)团簇各种可能的构型进行几何结构优化,预测了各团簇的最稳定结构.并对最稳定结构的平均结合能(Eb),二阶能量差分(Δ2E)和能隙(Eg)等进行了理论研究.结果表明,随着原子个数的增加,SiC二元团簇的结构由线性转变为平面,再转变为三维立体结构,原子数小于5时,除Si5和Si4C外其他所有的团簇都是平面结构;随着C原子增加,SimCn(m+n≤7)团簇的平均单点能不断增加,说明富C簇要比富Si稳定,对Sin团簇掺杂C原子可以提高团簇的稳定性;Cn,SiCn和Si2Cn团簇表现出明显的"奇-偶"振荡和"幻数"效应,Si2C,Si3C,Si5C,SiC2,Si3C2,Si4C2和SiC4团簇比其他团簇更稳定.
Possible geometrical structures and relative stability of Sin Cn （m ＋ n ≤ 7） clusters are studied by using the hybrid density functional theory （B3LYP） with 6-31G ＊basis sets in this article. For the most stable isomers of SimCn （m ＋ n ≤7） clusters, the binding energy per atom （Eb）, second difference in energy （△2 E） and HOMO-LUMO gaps （Eg） et al. are analyzed. The calculated results show that： with increasing of the number of atoms the structure of SiC binary clusters transform linear into planar, and then into a three-dimensional structure. When the atomic number is less than 5, all clusters have planer structure except for Si5 and Si4C. With the increase of C atom, the average binding energy of SimCn （m ＋ n ≤7） clusters increases, which means that clusters of ＂rich C＂ are more stable than clusters of ＂rich Si＂, and Sin clusters with C doping can increase the stability. Cn, SiCn and Si2 Cn clusters show clearly ＂odd-even＂ oscillation and the ＂magic number＂ effect, and Si2 C, Si3 C, Si5 C, SiC2 , Si3 C2 , Si4 C2 and SiC4 clusters are more stable than other clusters.
出处
《物理学报》
SCIE
EI
CAS
CSCD
北大核心
2009年第5期3104-3111,共8页
Acta Physica Sinica
基金
国家自然科学基金(批准号:10674114)资助的课题~~
