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arXiv 1506.03480cond-mat.mtrl-sciphysics.chem-ph
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吸附物在金属表面结合的多体色散效应

Many-body dispersion effects in the binding of adsorbates on metal surfaces

Reinhard J. Maurer, Victor G. Ruiz, Alexandre Tkatchenko

摘要:

正确描述与扩展(金属)表面接触的分子的电子交换和相关效应是第一性原理建模的一项具有挑战性的任务。在这项工作中,我们证明了集体范德华色散效应的重要性,超越了成对近似的有机-无机系统的原子,分子和纳米结构吸附在金属上的例子。我们在密度泛函理论的背景下使用最近开发的多体色散(MBD)方法[Phys. Rev. Lett. 108,236402(2012); J.Chem.Phys.140,18 A508(2014)],并评估其正确描述吸附物在金属表面上的结合的能力。我们简要回顾MBD方法,并强调其相似之处量子化学方法的电子相关的准粒子图片。特别地,我们研究了氙、3,4,9,10-二萘嵌苯四羧酸(PTCDA)和吸附在Ag(111)表面上的石墨烯片的结合性质。考虑到MBD效应,我们能够描述各向异性极化率张量的变化,改善吸附质振动的描述,并正确捕获吸附质-表面相互作用筛选。与其他方法和实验的比较表明,包含MBD效应通过减少通常在成对添加剂分散校正方法中发现的过结合来改善吸附能和几何形状。

英文摘要:

A correct description of electronic exchange and correlation effects for molecules in contact with extended (metal) surfaces is a challenging task for first-principles modeling. In this work we demonstrate the importance of collective van der Waals dispersion effects beyond the pairwise approximation for organic--inorganic systems on the example of atoms, molecules, and nanostructures adsorbed on metals. We use the recently developed many-body dispersion (MBD) approach in the context of density-functional theory [Phys. Rev. Lett. 108, 236402 (2012); J. Chem. Phys. 140, 18A508 (2014)] and assess its ability to correctly describe the binding of adsorbates on metal surfaces. We briefly review the MBD method and highlight its similarities to quantum-chemical approaches to electron correlation in a quasiparticle picture. In particular, we study the binding properties of xenon, 3,4,9,10-perylene-tetracarboxylic acid (PTCDA), and a graphene sheet adsorbed on the Ag(111) surface. Accounting for MBD effects we are able to describe changes in the anisotropic polarizability tensor, improve the description of adsorbate vibrations, and correctly capture the adsorbate--surface interaction screening. Comparison to other methods and experiment reveals that inclusion of MBD effects improves adsorption energies and geometries, by reducing the overbinding typically found in pairwise additive dispersion-correction approaches.

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