Abstract By ab initio molecular dynamics (AIMD) simulations and density-functional theory (DFT) calculations, we studied the kinetics and energetics of oxygen absorption on clean and Mo-doped γ-U (1 1 0) surface. The AIMD simulations shows that O2 will dissociates into separate O atoms, which are finally adsorbed on the surface. The doping Mo can change the final adsorption sites of O atoms. In addition, we found that temperature can accelerate O2 dissociation on γ-U (1 1 0) surface. The calculation of adsorption energies shows that the most preferred site for O atoms on the γ-U (1 1 0) surface is the short bridge site, followed by the 3-fold hollow. The doping Mo will decrease the adsorption energies of all the adsorption sites. With Mo-doping, the most preferred site for O atom is still short bridge. But, the second preferred adsorption site become long bridge. For clean and Mo-doped surfaces, the on-top is the least preferred adsorption site for atomic oxygen. Through calculations of diffusion pathways, we found Mo-doping raise the energy barrier for O atom diffusion on the surface. By the calculated segregation energies, it is found that the Mo atom prefers to locate in γ-U “bulk” rather than the top layer of the surface.

中文翻译：

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γ-U(1 1 0)表面氧吸附的第一性原理研究及Mo掺杂的影响

摘要 通过从头分子动力学(AIMD) 模拟和密度泛函理论(DFT) 计算，我们研究了清洁和Mo 掺杂γ-U (1 1 0) 表面吸氧的动力学和能量学。AIMD 模拟表明，O2 将分解成单独的 O 原子，最终吸附在表面上。掺杂Mo可以改变O原子的最终吸附位点。此外，我们发现温度可以加速 γ-U (1 1 0) 表面的 O2 解离。吸附能的计算表明，γ-U (1 1 0) 表面上 O 原子最优选的位置是短桥位，其次是 3 倍空心。掺杂钼会降低所有吸附位点的吸附能。对于 Mo 掺杂，O 原子最优选的位置仍然是短桥。但，第二个优选的吸附位点成为长桥。对于清洁和 Mo 掺杂的表面，顶部是原子氧最不优选的吸附位点。通过扩散路径的计算，我们发现Mo掺杂提高了O原子在表面扩散的能垒。通过计算的偏析能，发现 Mo 原子更喜欢位于 γ-U“主体”而不是表面的顶层。