H在Ni表面的扩散性质及表面缺陷的影响—嵌入原子法(EAM)计算研究

PROPERTIES OF THE SURFACE DIFFUSION AND THE EFFECTS OF THE SURFACE DEFECTS FOR H ON Nl SURFACES—EAIVl STUDIES

本文用原子集团模型和嵌入原子方法,计算研究了H在Ni(100),(110)和(111)表面上的扩散特性,其扩散激活能分别是0.152eV;0.343eV和0.142eV。Ni(100)面上的吸附Ni原子和Ni原子空位,分别是在其表面上扩散的H原子的一种陷阱和位垒;Ni(100)面上的台阶,将使通过此台阶的H原子的扩散势垒增高,激活能增大,且引起扩散的各向异性。

The properties of the surface diffusion (SD) and the effects of the surfaces defects are studied using the cluster models and the embedded atom method (EAM).The results show that the activation energies of SD of H on Ni(100),(110) and (111) are 0.152eV,0.343eV and 0.142eV respectively.A adsorbeded Ni atom on Ni(100) is a trap while a vacancy is a barrier.A step on Ni(100) will increase the potential barrier and activation energy for the diffusing H atom across this step, and causing the anisotropy of SD of H on the stepped Ni surface.