Abstract The three low index surfaces of nickel, {1 0 0}, {1 1 0} and {1 1 1}, have been investigated to question the crystallographic orientation impact on hydrogen diffusivity and solubility near the surface. Diffusion profiles from Top adsorption sites underlined that subsurface migration barriers were different from the bulk and vary depending on the crystallographic orientation, revealing a local anisotropic diffusive behavior. The local geometry change of the successive occupied octahedral sites due to surface relaxation and H incorporation have also been investigated using nickel atoms positions of relaxed structures. The surface contraction effect on local octahedral sites appeared to be comparable to a vacancy effect on its nearest neighboring sites, both in terms of spatial extend and contraction magnitude. The hydrostatic contribution to H incorporation seemed to dominate the associate internal elastic energy, leading to a good description of local H solubility with the available volume. Local anisotropy at the surface proximity in terms of diffusivity and solubility were contained within the first atomic layers.

中文翻译：

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镍单晶表面附近的氢溶解度和扩散率：弹性能的一些含义

摘要 研究了镍的三个低指数表面 {1 0 0}、{1 1 0} 和 {1 1 1}，以质疑晶体取向对表面附近氢扩散率和溶解度的影响。来自顶部吸附位点的扩散曲线强调了地下迁移障碍与本体不同，并且根据晶体取向而变化，揭示了局部各向异性扩散行为。还使用松弛结构的镍原子位置研究了由于表面松弛和 H 掺入而导致的连续占据的八面体位置的局部几何变化。在空间扩展和收缩幅度方面，局部八面体站点的表面收缩效应似乎与其最近的相邻站点的空位效应相当。流体静力对 H 掺入的贡献似乎主导了相关的内部弹性能，从而可以很好地描述局部 H 溶解度与可用体积。就扩散率和溶解度而言，表面邻近处的局部各向异性包含在第一原子层内。