【摘要】 基于密度泛函理论(DFT)中的广义梯度近似(GGA)对Cd_n(2≤n≤13)团簇进行了结构优化.其基态结构由较为松散平面结构向紧凑型堆积,主要以三角或四角双锥结构为基本单元,通过边戴帽或面戴帽形成较为稳定的Cd_n团簇.随着原子数目增加,Cd_n(2≤n≤13)团簇的稳定性在增强,结合该团簇的HOMO-LUMO能隙分布,发现n=4,10是镉团簇的幻数.通过电荷转移和垂直电离势(VIPs)计算发现n=6是Cd_n团簇原子间相互作用力由范德华力向共价键结合方式转变的转折点.更多还原

【Abstract】 Here the geometries of the Cd_n(2≤n≤l3) clusters have been optimized using density functional theory with generalized gradient approximation(GGA) for exchange-correlation functional.The ground state structures change from incompact planar structures to close-packed structures,and they are mainly based on the trigonal bipyramid or tetragonal bipyramid structure,then forming the steady Cd_n clusters by mean of the side or surface Cd-capped.The stability of Cd_n(2≤n≤l3) clusters increase as the number of n increases,combining the analysis of the energy gaps between the highest occupied and lowest unoccupied molecular orbitals(HOMO-LUMO),it is found that n = 4,10 are magic numbers for Cd clusters.According to the transfer of the electric charge and the vertical ionization potentials(VIPs), the calculated results indicate that n=6 is the turning point form van der Waals to covalent bond behavior in Cd clusters.更多还原