(C_2H)_2M_n(M=Cu、Ag、Au;n=1-4)团簇的密度泛函理论研究

Investigation on(C_2H)_2M_n(M=Cu,Ag,Au;n=1-4)clusters with density functional theory

采用密度泛函理论的B3LYP和PBEIPBE方法,对(C_2H)_2M_n(M=Cu、Ag、Au;n=1-4)团簇的结构和性质进行了研究。结果表明:(C_2H)_2M_n(M=Cu、Ag、Au;n=1-4)簇的最稳定结构都是在C_2HM_n(M=Cu、Ag、Au;n=1-4)簇最稳定结构的基础上,又与C_2H自由基相互作用的结果。NBO计算结果表明:银与2个C_2H自由基的相互作用弱于铜和金。(C_2H)_2M_n(M=Cu、Ag、Au;n=1-4)簇最稳定结构的相互作用能均为负值,表明形成的团簇较稳定,并且出现了奇-偶振荡效应(n=1-4),含偶数个IB原子的团簇比含奇数个IB原子的团簇稳定。红外分析表明:(C_2H)_2M_n(M=Cu、Ag、Au;n=1-4)团簇中C_2H自由基的C≡C和C-H键的伸缩振动都发生了红移,随着团簇尺寸的增加(n=1-4),也出现了奇-偶振荡效应。

The structure and property of （C2H）2Mn（M=Cu, Ag, Au; n= 1-4） clusters were studied based on the density functional theory （DFT） with B3LYP and PBE1PBE method. The results showed that the most stable structures of （C2H）2Mn（M=Cu, Ag, Au; n=1-4） clusters could be regarded as interacting with another C2H radical on the structures of C2HMn （M=Cu, Ag, Au; n=1-4） clusters, Natural bond orbital （NBO） calculations indicated that the interaction of silver with C2H radicals was the weakest among gold, silver and copper. The interaction energy of the clusters was negative, implying that the stable clusters were formed. The interaction energy displayed odd-even oscillations and the even-numbered IB atom of clusters were relatively more stable than the odd-numbered clusters. Infrared analysis revealed that the C=C and C-H stretching vibration of the C2H radical in （C2H）2Mn （M=Cu, Ag, Au; n=1-4） clusters was red shifted, and with the cluster size （n=1-4） increasing, odd-even oscillations effect occurred.