本文用 Si₃₉H₃₂, Si₃₅H₃₀, Si₉₁H₆₄ 和 Si₅₈H₄₆ 原子集团模型模拟 Si (112)高密 勒指数面, 探讨了模拟 Si (112) 表面模型的选取, 计算了诸原子集团中的电荷分布。发现, Si (112) 表面元胞所处的环境对表面元胞中电荷分布性质有 根本影响, 大规模原子集团模型 Si₉₁H₆₄ 较好地模拟了 Si (112) 表面的性质。不同的模型下都得到一个共同的电子结构特性, 即表面原子 在悬键方向存在电荷的趋向集居, 且这种性质对台面原子尤为明显。这个结果说明,表面电荷的趋向集居是由表面原子的结构特点决定的。

Large cluster models of Si₃₉H₃₂, Si₃₅H₃₀, Si₉₁H₆₄ and Si₅₈H₄₆ were used to simulate the Si (112) surface, respectively. The net charge and its distribution of these systems were calculated by means of semiempirical CNDO-SCF method. The results indicate that the cluster models Si₃₉H₃₂ and Si₃₅H₃₀ are not large enough to simulate the Si (112) surface, and the cluster of Si₉₁H₆₄ is a reasonable one for modeling Si (112) surface. The authors also found that the net charges existing at surface atoms are concentrated in the direction (or in the opposite direction) of the corresponding dangling bonds. This property is determined by the atomic structure of the surface.