H原子在γ-U(100)表面吸附与扩散的密度泛函研究

Density Functional Study of Hydrogen Atomic Adsorption and Transportation on γ-U(100) Surface

摘要: 采用密度泛函理论方法研究了H原子在γ-U(100)表面的吸附和扩散。结果表明：H原子在γ-U(100)表面的最佳吸附位依次为穴位、桥位和顶位，吸附能分别为2.696、2.597和2.017 eV；H原子在γ-U中的最佳间隙位为四面体间隙，其次是八面体间隙，吸附能分别为1.534 eV和0.991 eV；H原子在铀表面以及近表面层的不同吸附位之间的扩散需克服不同的势垒，相比于间隙位，H原子更倾向于在γ-U(100)表面吸附聚集。

Abstract: The adsorption and transportation of hydrogen atom on γ-U(100) surface were studied by the density functional theory (DFT). The results show that the most stable adsorption site on the surface is the center site, then the bridge site and top site. The adsorption energy is 2.696, 2.597 and 2.017 eV, respectively. The most stable interstitial site for hydrogen atom in γ-U is the tetrahedral (tet) site then the octahedral (oct) site. The adsorption energy is 1.534 eV for tet site and 0.991 eV for oct site. There are different barriers for hydrogen atom to transport through the various adsorption sites and hydrogen atom prefers to enrich on the surface sites rather than enrich in the interstitial sites.