Eu_mSi_n(m=1～2,n=1～8)团簇结构和性质的密度泛函理论研究

在密度泛函理论的框架下,采用广义梯度近似（GGA）研究了Eu₂Si_n（n=1～7）团簇的基态几何结构,系统计算了平均结合能E_b、二阶能量差分△₂E、最高占据轨道（HOMO）与最低未占据轨道（LUMO）之间的能隙,并与已有的EuSi_n（n=2～8）团簇相关数据作对比分析.研究表明:单Eu原子比双Eu原子掺杂的Si团簇具有更高的稳定性,EuSi₃、EuSi₆、Eu₂Si₄团簇较相应邻近团簇结构稳定;Eu_mSi_n（m=1～2,n=l～8）团簇的能隙随着团簇总原子数的增加呈现振荡变化,态密度分析得到能隙振荡变化的原因是S原子的s轨道与Eu原子的p轨道发生了杂化.

Density functional theory study on the structures and properties of EumSin(m=1-2, n=1-8) clusters

The ground state geometry structure of the Eu2Sin(n=1-7) clusters are investigated using the generalized gradient approximation(GGA) under the density functional theory framework. We calculated the binding energy per atom(Eb), the second-order difference of energies, the gap between the highest occupy orbit(HOMO) and the lowest unoccupy orbit(LUMO) . Comparing with the related data of the existing EuSin(n=2-8) clusters, our results implied that single Eu atom doped Si clusters are more stable than double Eu and the EuSi3, EuSi6, Eu2Si4 are more stable than corresponding neighboring clusters. Additionally, the energy gap of EumSin(m=1-2, n=1-8) clusters oscillate with the increase of the total number of atoms and the reason is that the hybridization of s orbital of Si atom with p orbital of Eu atom according to the density of states.