H原子在Zr(0001)表面吸附的第一性原理研究

First-Principle Study of H Atom Adsorption on Zr(0001) Surface

结合蒙特卡洛(MC)模拟和第一性原理密度泛函理论(DFT)方法,从Zr-H体系微观结构、吸附概率、吸附能、Mulliken电荷布居数以及电子态密度等方面对H原子在α-Zr(0001)表面的吸附位点和吸附机理等进行计算分析。结果表明:H原子在Zr(0001)表面首先产生物理吸附,然后由物理吸附转变为化学吸附,吸附过程中电荷不断由Zr(0001)表面原子向H原子转移,最后趋于稳定。另外,稳定吸附后的H原子直接与Zr(0001)表面最表层原子生成化学键,且主要由H(s)、Zr(s)和Zr(d)轨道的电子态做贡献。综合分析得到H原子在Zr(0001)表面的吸附位点优先级顺序为密排六方间隙位(hcp位)>面心立方间隙位(fcc位)>桥位(bridge位),顶位(top位)不会产生吸附。

The adsorption sites and mechanism of H atom on α-Zr(0001) surface were calculated and analyzed from microstructure, adsorption probability, adsorption energy, Mulliken charge population and density of state, and etc. based on the integration of Monte Carlo(MC) simulation and first-principle density functional theory(DFT) method. The results indicated that the H atom firstly generated physical adsorption on the Zr(0001) surface and then changes to chemical adsorption. The charge continuously transferred from the surface Zr(0001) atoms to the H atom throughout the entire process, and finally stabilized. Furthermore, the H atom directly bonded with the most surface Zr(0001) atoms after stable adsorption, and the major contribution of Zr-H bond was made by partial density of state of H(s), Zr(s) and Zr(d) orbitals. Comprehensive analysis shows that the priority order of the adsorption sites of H atoms on the Zr(0001) surface is hexagonal close packed gap(hcp)> face centered cubic gap(fcc)>bridge, and the top site is the impossible adsorption site.