Zhao Gao-feng, Zhang Jun, Jing Qun, Luo You-hua, Wang Yuan-xu
School of Physics and Electronics, Henan University, Kaifeng 475004, People's Republic of China.
J Chem Phys. 2007 Dec 21;127(23):234312. doi: 10.1063/1.2806991.
The geometries, stabilities, and electronic and magnetic properties of Y(n)Al (n=1-14) clusters have been systematically investigated by using density functional theory with generalized gradient approximation. The growth pattern for different sized Y(n)Al (n=1-14) clusters is Al-substituted Y(n+1) clusters and it keeps the similar frameworks of the most stable Y(n+1) clusters except for Y(9)Al cluster. The Al atom substituted the surface atom of the Y(n+1) clusters for n<9. Starting from n=9, the Al atom completely falls into the center of the Y-frame. The Al atom substituted the center atom of the Y(n+1) clusters to form the Al-encapsulated Y(n) geometries for n>9. The calculated results manifest that doping of the Al atom contributes to strengthen the stabilities of the yttrium framework. In addition, the relative stability of Y(12)Al is the strongest among all different sized Y(n)Al clusters, which might stem from its highly symmetric geometry. Mulliken population analysis shows that the charges always transfer from Y atoms to Al atom in all different sized clusters. Doping of the Al atom decreases the average magnetic moments of most Y(n) clusters. Especially, the magnetic moment is completely quenched after doping Al in the Y(13), which is ascribed to the disappearance of the ininerant 4d electron spin exchange effect. Finally, the frontier orbitals properties of Y(n)Al are also discussed.
采用广义梯度近似密度泛函理论系统研究了Y(n)Al（n = 1 - 14）团簇的几何结构、稳定性以及电子和磁性性质。不同尺寸的Y(n)Al（n = 1 - 14）团簇的生长模式是Al取代的Y(n + 1)团簇，除了Y(9)Al团簇外，它保持了最稳定的Y(n + 1)团簇的相似框架。对于n < 9，Al原子取代了Y(n + 1)团簇的表面原子。从n = 9开始，Al原子完全落入Y框架的中心。对于n > 9，Al原子取代了Y(n + 1)团簇的中心原子以形成Al包裹的Y(n)几何结构。计算结果表明，Al原子的掺杂有助于增强钇框架的稳定性。此外，Y(12)Al在所有不同尺寸的Y(n)Al团簇中相对稳定性最强，这可能源于其高度对称的几何结构。Mulliken布居分析表明，在所有不同尺寸的团簇中，电荷总是从Y原子转移到Al原子。Al原子的掺杂降低了大多数Y(n)团簇的平均磁矩。特别是，在Y(13)中掺杂Al后磁矩完全淬灭，这归因于巡游4d电子自旋交换效应的消失。最后，还讨论了Y(n)Al的前沿轨道性质。
