(1. 昆明理工大學(xué) 真空冶金國家工程實驗室，昆明 650093；
2. 昆明理工大學(xué) 云南省有色金屬真空冶金重點實驗室，昆明 650093；
3. 昆明理工大學(xué) 云南省復(fù)雜有色金屬資源清潔利用國家重點實驗室(培育基地)，昆明 650093)
摘 要: 采用密度泛函理論(DFT)中的廣義梯度近似(GGA)對MomSn(m+n≤8)團簇進行結(jié)構(gòu)優(yōu)化，通過計算其二階能量差分Δ2Em、分裂能D(m)、平均結(jié)合能Eb、最高占據(jù)軌道(HOMO)、最低空軌道(LUMO)和HOMO-LUMO能隙HLG，以表征與分析團簇總原子數(shù)對MomSn團簇基態(tài)結(jié)構(gòu)穩(wěn)定性的影響。計算結(jié)果表明：隨著總原子數(shù)(m+n)的增大，MomSn團簇的基態(tài)結(jié)構(gòu)由較為松散的平面結(jié)構(gòu)向緊湊型的空間結(jié)構(gòu)轉(zhuǎn)變，其基態(tài)幾何構(gòu)型與Sn團簇以及Mom團簇的基態(tài)幾何構(gòu)型密切相關(guān)；MomSn團簇結(jié)構(gòu)穩(wěn)定性隨團簇原子總數(shù)(m+n)的增加而增大，MomSn團簇的平均結(jié)合能比Sn團簇和Mom團簇的平均結(jié)合能要大；MoSn團簇、Mo2Sn團簇、Mo3Sn團簇的幻數(shù)(n)分別為5、4、3；在MomSn團簇中，電荷均是由Mo原子向S原子轉(zhuǎn)移的，并以共價鍵和離子鍵共存。
關(guān)鍵字: 密度泛函理論；MomSn團簇；基態(tài)結(jié)構(gòu)；振動頻率；平均結(jié)合能；Mulliken布局
（1. National Engineering Laboratory for Vacuum Metallurgy,
Kunming University of Science and Technology, Kunming 650093, China;
2. Key Laboratory of Vacuum Metallurgy for Non-ferrous Metal of Yunnan Province,
Kunming University of Science and Technology, Kunming 650093, China;
3. State Key Laboratory Breeding Base of Complex Non-ferrous Metal Resources Clear Utilization in Yunnan Province,
Kunming University of Science and Technology, Kunming 650093, China）
Abstract:The geometries of the MomSn(m+n≤8) clusters were optimized using density functional theory(DFT) with generalized gradient approximation(GGA) for exchange-correlation functional. Several parameters, such as the second difference of energies(Δ2Em), the fission energy(D(m)), average binding energy(Eb), highest occupied molecular orbital(HOMO), lowest unoccupied molecular orbital(LUMO) and the HOMO-LUMO energy gap(HLG), were calculated to characterize and analyze the influence of total atom number on the structural stabilities of MomSn clusters. The calculated results show that the ground state structures change from incompact planar structures to closed-packed structures with the increase of total atom number (m+n), the ground state structures are mainly based on the ground state structures of Sn clusters and Mom clusters. And the structural stabilities of MomSn clusters increase with the increase of total atom number, and the average binding energy of MomSn clusters is higher than those of Sn clusters and Mom clusters. when the magic numbers (n) of MoSn clusters, Mo2Sn clusters and Mo3Sn clusters are 5, 4, and 3, respectively, the charge transfers from Mo atom to S atom in MomSn clusters and the co-existence of covalent and ionic bond can be found.
Key words: density functional theory; MomSn cluster; ground state structure; vibrational frequency; average binding energy; Mulliken population
