arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1104.2152cond-mat.mtrl-sciphysics.chem-ph
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水在Zr(0001)表面吸附和解离的密度泛函理论研究

Adsorption and dissociation of water on Zr(0001) with density-functional theory studies

Shuang-Xi Wang, Ping Zhang, Peng Zhang, Jian Zhao, Shu-Shen Li

摘要:

采用密度泛函理论研究了孤立水分子在Zr(0001)表面的吸附和解离。两种具有几乎相同吸附能的吸附构型被确定为局部稳定状态,即,分别为扁平和直立配置。结果表明,顶位上的平坦吸附态主要由1 $b_{1}$ - $d$带耦合控制,对方位角取向不敏感.相邻顶部位置之间的扩散揭示了水分子在表面上是非常活跃的。对于直立构型,我们发现除了分子轨道1 $b_{1}$和3 $a_{1}$的贡献外,发生在费米能级上的表面$\rightarrow$水电荷转移也起着重要的作用. H $_{2}$ O的解离被发现是非常容易的,特别是对于直立构型,与可获得的实验结果很好地一致。研究结果为深入了解锆的水致表面腐蚀提供了指导。

英文摘要:

The adsorption and dissociation of isolated water molecule on Zr(0001) surface are theoretically investigated for the first time by using density-functional theory calculations. Two kinds of adsorption configurations with almost the same adsorption energy are identified as the locally stable states, i.e., the flat and upright configurations respectively. It is shown that the flat adsorption states on the top site are dominated by the 1$b_{1}$-$d$ band coupling, insensitive to the azimuthal orientation. The diffusion between adjacent top sites reveals that the water molecule is very mobile on the surface. For the upright configuration, we find that besides the contribution of the molecular orbitals 1$b_{1}$ and 3$a_{1}$, the surface$\rightarrow$water charge transfer occurring across the Fermi level also plays an important role. The dissociation of H$_{2}$O is found to be very facile, especially for the upright configuration, in good accordance with the attainable experimental results. The present results afford to provide a guiding line for deeply understanding the water-induced surface corrosion of zirconium.

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