Department of Physics, Northwest University, Xi'an 710069, China.
J Chem Phys. 2013 Mar 7;138(9):094304. doi: 10.1063/1.4793276.
Following the recent work of decomposing the total dipole moment and polarizability of a homogeneous system into site-specific contributions, we extend the study to the heterogeneous systems of iron-doped Sin (n = 1-14) clusters by introducing a weighting function. The structure-∕shape- and size-specific aspects of the dipole moments and polarizabilities of SinFe (n = 1-14) clusters are analyzed and compared with pure silicon clusters. It is shown that the polarizabilities associated with the individual constituent atoms vary considerably with the structure∕shape of the cluster and the location of the atom or site within a given structure. For atoms at peripheral sites, the polarizabilities are substantially larger than atoms at the interior sites, and the more peripheral an atom is, the larger is its polarizability. The polarizability of the Fe atom in SinFe clusters decreases as the cluster size increases. This is related to the position of Fe atom in SinFe clusters and indicates significant screening of the interior of the cluster by its surface. The correlation between the anisotropy of the total polarizability and the anisotropy of the cluster shape is also analyzed. Comparing with pure Sin clusters, the polarizabilities of Si atoms are increased after Fe atom doping. The structures are more compact for SinFe than the same sizes of Sin +1 clusters and the polarizabilities of SinFe are smaller than Sin +1 for the sizes of n = 7-14.
继最近将均匀体系的总偶极矩和极化率分解为特定位置的贡献的工作之后，我们通过引入权重函数将研究扩展到掺杂铁的 Sin（n = 1-14）团簇的非均匀体系。分析了 SinFe（n = 1-14）团簇的偶极矩和极化率的结构-形状-和尺寸特异性方面，并与纯硅团簇进行了比较。结果表明，与单个组成原子相关的极化率随团簇的结构/形状以及原子在给定结构中的位置而变化很大。对于外围位置的原子，极化率远大于内部位置的原子，并且原子越外围，其极化率越大。SinFe 团簇中 Fe 原子的极化率随团簇尺寸的增加而减小。这与 SinFe 团簇中 Fe 原子的位置有关，表明其表面对团簇内部有明显的屏蔽作用。还分析了总极化率各向异性与团簇形状各向异性之间的相关性。与纯 Sin 团簇相比，Fe 原子掺杂后 Si 原子的极化率增加。对于 n = 7-14 的尺寸，与相同尺寸的 Sin +1 团簇相比，SinFe 的结构更紧凑，且 SinFe 的极化率小于 Sin +1。
