Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 10617, Taiwan.
J Phys Condens Matter. 2012 Oct 3;24(39):395002. doi: 10.1088/0953-8984/24/39/395002. Epub 2012 Aug 22.
We have performed calculations of adsorption energetics on the graphene surface using the state-of-the-art diffusion quantum Monte Carlo method. Two types of configurations are considered in this work: the adsorption of a single O, F, or H atom on the graphene surface and the H-saturated graphene system (graphane). The adsorption energies are compared with those obtained from density functional theory with various exchange-correlation functionals. The results indicate that the approximate exchange-correlation functionals significantly overestimate the binding of O and F atoms on graphene, although the preferred adsorption sites are consistent. The energy errors are much less for atomic hydrogen adsorbed on the surface. We also find that a single O or H atom on graphene has a higher energy than in the molecular state, while the adsorption of a single F atom is preferred over the gas phase. In addition, the energetics of graphane is reported. The calculated equilibrium lattice constant turns out to be larger than that of graphene, at variance with a recent experimental suggestion.
我们使用最先进的扩散量子蒙特卡罗方法在石墨烯表面上进行了吸附能的计算。在这项工作中考虑了两种类型的构型：单个 O、F 或 H 原子在石墨烯表面上的吸附和 H 饱和的石墨烯体系（石墨烷）。吸附能与各种交换相关泛函的密度泛函理论结果进行了比较。结果表明，尽管首选的吸附位一致，但近似交换相关泛函会显著高估 O 和 F 原子在石墨烯上的结合能。对于吸附在表面上的原子氢，能量误差要小得多。我们还发现，单个 O 或 H 原子在石墨烯上的能量高于分子态，而单个 F 原子的吸附优先于气相。此外，还报告了石墨烷的能态。计算得出的平衡晶格常数大于石墨烯，与最近的实验建议不一致。
