Wang Yang, Alcamí Manuel, Martín Fernando
Departamento de Química, C-9, Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, Spain.
Chemphyschem. 2008 May 16;9(7):1030-5. doi: 10.1002/cphc.200700725.
We report a DFT study on the self-assembly of the fullerene derivative PCBM on the Au(111) surface. Recent STM experiments (Angew. Chem. 2007, 119, 8020-8023([1])) show a coverage-dependent transition of the adsorption and self-assembly of PCBM on this surface. To understand the origin of this observation, we compute the geometries and relative energies of ten PCBM dimers and four tetramers. The calculations show that the self-assembly of PCBM at high coverage is mainly controlled by hydrogen bonding between the PCBM tails. Due to the large size of the fullerene cage, the hydrogen bonds are formed far away from the surface; hence they are very similar to those found in the gas phase. This picture successfully explains the observed site-insensitive adsorption at high coverage and the 2D arrangement of PCBM on the surface.
我们报告了一项关于富勒烯衍生物PCBM在Au(111)表面自组装的密度泛函理论（DFT）研究。最近的扫描隧道显微镜（STM）实验（《应用化学》2007年，119卷，8020 - 8023页([1])）表明，PCBM在该表面的吸附和自组装存在与覆盖率相关的转变。为了理解这一观察结果的起源，我们计算了十个PCBM二聚体和四个四聚体的几何结构和相对能量。计算结果表明，高覆盖率下PCBM的自组装主要由PCBM尾部之间的氢键控制。由于富勒烯笼的尺寸较大，氢键在远离表面的位置形成；因此它们与气相中发现的氢键非常相似。这一情况成功地解释了在高覆盖率下观察到的对吸附位点不敏感以及PCBM在表面的二维排列。
