密度泛函理论研究Run和RunAu(n=1-12)团簇的结构和电子性质

The study on structures and properties of Ru_n and Ru_n Au(n=1—12) clusters by density functional theory

采用密度泛函理论中的广义梯度近似(GGA)对RunAu和Run团簇的几何构型进行优化,并对能量、频率、电子性质和磁性质进行了计算.结果表明,RunAu团簇的最低能量结构可以通过Au原子代替Run+1团簇中的Ru原子生长而成.除了局域的结构畸变,RunAu和Run+1团簇具有相似的几何结构.二阶能量差分、电离势、亲和势和分裂能表明Ru5,Ru8,Ru5Au,Ru8Au是稳定的团簇,Au的掺杂没有改变Run的相对稳定性.通过电子性质的分析发现,当Au原子掺杂在Run中,团簇的化学活性增加,且团簇的能隙主要由电子的配对效应决定;对于大多数团簇来说,Au原子掺杂提高了RunAu的磁矩.

The geometries,the stabilities,and the electronic properties of RunAu and Run（n=1—12） clusters are systematically investigated by the density functional theory.The results suggest that the lowest energy structures for RunAu clusters can be obtained by substituting one Ru atom in Run＋1 clusters with Au atom.The geometries of RunAu clusters are similar to those of Run＋1 clusters except local structural distortions.The second-order difference and fragmentation energy show that Ru5,Ru8,Ru5Au,and Ru8Au clusters are the most stable among these studied clusters,the doped Au atoms do not change the relative stabilities of Run clusters;the Au impurities increase the chemical activities of Run clusters,and the value of gap is determined mainly by the electron-pairing effect;the doped Au atoms increase the total magnetic moments of Run Au in most cases.