Au(110)表面结构和氧原子吸附的第一性原理研究

Density-functional theory investigation of atomic geometry and oxygen adsorption of Au(110) surface

用密度泛函理论(DFT)研究了金属Au(110)表面结构以及氧原子的吸附状态.计算得到Au(110)-(1×2)缺列再构表面原子的弛豫分别是-15.0%(Δd12/d0)和-1.1%(Δd23/d0),表面能为52.7meV/2,功函数Φ=5.00eV;Au(110)-(1×3)缺列再构表面的Δd12/d0=-20.5%,Δd23/d0=+2.7%,表面能53.4meV/2,Φ=4.98eV.计算模拟了它们的STM图像并记录了STM针尖的起伏变化.研究发现Au(110)-p(1×1)和p(1×2)再构表面的氧吸附,在高覆盖下各吸附位置的吸附能值均为负值,发生的吸附可视为吸热过程.说明Au(110)表面基本上与氧不发生吸附和反应,具有很高的化学惰性.

We have performed density-functional theory calculations of the atomic structure and the oxygen adsorption properties of Au（110） surfaces.The relaxations of missing-row reconstructed Au（110）-（1 × 2） surface are calculated to be 15.0%（Δd12 /d0） and-1.1%（Δd23 /d0）.The relevant surface energy and workfunction are calculated to be 52.7 meV /2 and 5.00 eV,respectively.In the case of missing-row reconstructed Au（110）-（1 × 3） surface the surface atomic relaxations are calculated to be-20.5 %（Δd12 /d0） and ＋ 2.7 %（Δd23 /d0） which are quite differente from those of Au（110）-（1 × 2）.However,in the later case,the surface energy and workfunction are found to be very close to those of missing-row reconstructed Au（110）-（1 × 2） surface,i.e.,53.4 meV /2 and 4.98 eV.We have simulated the scanning tunneling microscope（STM） images of both reconstructed surfaces and found that the missing row exhibits a remarkable hollow in the STM morphology.The further calculation of oxygen adsorption on both surfaces reveals that the adsorption energies in these cases are negative.These results indicate that the Au（110） surface is free from oxygen adsorption and reaction,showing highly chemical inertia.