氢原子和氧原子在双六元紧密堆积镅弛豫（0001）表面化学吸附的密度泛函研究
A Density Functional Study of Atomic Hydrogen and Oxygen Chemisorption on the Relaxed (0001) Surface of Double Hexagonal Close Packed Americium
摘要：
在密度泛函理论的框架下，采用全势能全电子线性缀加平面波加局域轨道方法，对氢原子和氧原子在双六方堆积的镅（0001）表面的化学吸附进行了从头算总能量计算.化学吸附能量进行了优化相对于吸附原子从松弛表面的三个吸附位点，即顶部，桥，和中空的六方桉网站，在所有情况下，吸附层结构对应于覆盖率的0.25单层的距离。在标量相对论水平（无自旋轨道耦合NSOC）和完全相对论水平（有自旋轨道耦合SOC）计算化学吸附能。在NSOC和SOC理论水平下，O的最稳定吸附位是两重桥吸附位，化学吸附能分别为8.204 eV和8.368 eV; H的最稳定吸附位是三重空心hcp吸附位，化学吸附能分别为3.136 eV和3.217 eV.发现H和O吸附原子与表面的距离分别为1.196 Ang。1.164安总的来说，我们的计算表明，在SOC的情况下，化学吸附能比NSOC的情况下，在0.049-0.238 eV的范围内，稍微更稳定。与裸dhcp Am（0001）表面相比，所有情况下的功函数和净磁矩分别增加和减少。利用松饼罐内的部分电荷、差分电荷密度分布和局域态密度详细分析了原子与原子间的键相互作用。化学吸附对Am 5 f电子定域-离域的影响也进行了讨论。
英文摘要：
Ab initio total energy calculations within the framework of density functional theory have been performed for atomic hydrogen and oxygen chemisorption on the (0001) surface of double hexagonal packed americium using a full-potential all-electron linearized augmented plane wave plus local orbitals method. Chemisorption energies were optimized with respect to the distance of the adatom from the relaxed surface for three adsorption sites, namely top, bridge, and hollow hcp sites, the adlayer structure corresponding to coverage of a 0.25 monolayer in all cases. Chemisorption energies were computed at the scalar-relativistic level (no spin-orbit coupling NSOC) and at the fully relativistic level (with spin-orbit coupling SOC). The two-fold bridge adsorption site was found to be the most stable site for O at both the NSOC and SOC theoretical levels with chemisorption energies of 8.204 eV and 8.368 eV respectively, while the three-fold hollow hcp adsorption site was found to be the most stable site for H with chemisorption energies of 3.136 eV at the NSOC level and 3.217 eV at the SOC level. The respective distances of the H and O adatoms from the surface were found to be 1.196 Ang. and 1.164 Ang. Overall our calculations indicate that chemisorption energies in cases with SOC are slightly more stable than the cases with NSOC in the 0.049-0.238 eV range. The work functions and net magnetic moments respectively increased and decreased in all cases compared with the corresponding quantities of bare dhcp Am (0001) surface. The partial charges inside the muffin-tins, difference charge density distributions, and the local density of states have been used to analyze the Am-adatom bond interactions in detail. The implications of chemisorption on Am 5f electron localization-delocalization are also discussed.
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