(湖南大學 材料科學與工程學院， 長沙 410082)
摘 要: 采用第一原理贗勢平面波方法計算Aln(n=2~24, 55)團簇的幾何、 能態(tài)與電子結(jié)構(gòu)， 通過結(jié)合能Eb、 HOMO-LUMO能隙ΔEH-L與能量二階差分Δ2E(n)表征和考察團簇原子數(shù)n對Aln團簇基態(tài)結(jié)構(gòu)穩(wěn)定性的影響。 結(jié)果表明： Aln團簇結(jié)構(gòu)穩(wěn)定性隨團簇原子數(shù)n增加而增大， 并在n為7, 11, 13, 19, 23等近幻數(shù)和高對稱性結(jié)構(gòu)處出現(xiàn)極值， 相對其臨近Aln團簇， 具有較高的結(jié)構(gòu)穩(wěn)定性。 DOS與吸收光譜分析表明， 隨著團簇內(nèi)部s-p電子雜化的逐漸增強， Aln團簇結(jié)構(gòu)的穩(wěn)定性也隨之增加， 但即使當團簇原子數(shù)n達到55時， 其微弱的表面效應仍不能消除。
關(guān)鍵字: 贗勢平面波方法； Aln團簇； 電子結(jié)構(gòu)； 結(jié)構(gòu)穩(wěn)定性
（School of Materials Science and Engineering, Hunan University,Changsha 410082, China）
Abstract: The geometries, energetics and electronic structure of neutral Aln(n=2-24, 55) clusters were calculated using the first-principles pseudo-potential plane wave method. The several parameters, such as binding energy Eb, HOMO-LUMO energy gap ΔEH-L, second difference of energies Δ2E(n) were utilized to characterize and analyze the structure stability of Aln cluster. The results show that the structure stability of Aln clusters increases with the increase of total atom number n. For Al7, Al11, Al13, Al19, Al23 clusters with nearly filled shell of the covalence electron number and high symmetry of geometrical structure, a high structure stability relative to their neighbor Aln clusters can be seen. The analysis of the DOS and absorption spectra shows that the increase of stability of Aln cluster mainly originates from the enhancement of s-p hybridization of Al atoms in cluster, but when up to n=55, the weak influences of surface energy caused by the size of cluster on the properties of Aln cluster can not be eliminated still.
Key words: pseudo-potential plane-wave method; Aln cluster; electronic structure; structural stability
