Kim Do Hwan, Choi Dae Sik, Kim Ansoon, Bae Sung-Soo, Hong Suklyun, Kim Sehun
Department of Chemistry and School of Molecular Science (BK 21), Korea Advanced Institute of Science and Technology, Daejeon 305-701, Republic of Korea.
J Phys Chem B. 2006 Apr 20;110(15):7938-43. doi: 10.1021/jp0521656.
The adsorption structures of pyrrole (C(4)H(5)N) on a Ge(100) surface at various coverages have been investigated with both scanning tunneling microscopy (STM) and ab initio density-functional theory (DFT) calculations. Three distinct features are observed in the STM images at low coverages. The comparison of the STM images with the simulation reveals that the most dominant flowerlike feature with a dark side is that the adsorbed pyrrole molecules with H dissociated form bridges between two down Ge atoms of neighboring Ge dimer rows through N-Ge bonding and beta-carbon-Ge interaction. The flowerlike feature without a dark side is also observed as a minority, which is identified as nearly the same structure as the most dominant one where a dissociated H is out of the feature. The third feature showing bright protrusions may be due to a C- and N-end-on (CN) configuration, where the pyrrole molecule is located on one dimer row. At higher coverages, the number of localized configurations increases.
利用扫描隧道显微镜（STM）和从头算密度泛函理论（DFT）计算，研究了吡咯（C(4)H(5)N）在不同覆盖度下在Ge(100)表面的吸附结构。在低覆盖度的STM图像中观察到三个明显特征。将STM图像与模拟结果进行比较发现，最主要的带有暗边的花状特征是，H解离的吸附吡咯分子通过N-Ge键和β-碳-Ge相互作用在相邻Ge二聚体行的两个向下的Ge原子之间形成桥连。不带暗边的花状特征也作为少数情况被观察到，它被确定为与最主要的结构几乎相同，只是一个解离的H不在该特征中。显示明亮突起的第三个特征可能是由于C端和N端朝上（CN）的构型，其中吡咯分子位于一个二聚体行上。在较高覆盖度下，局部构型的数量增加。
