苯在Ag(100)表面吸附的周期性密度泛函理论研究

 采用量子化学中的密度泛函理论结合平板周期模型方法,研究了苯在Ag(100)面上的吸附方式和相对稳定性. 通过对不同吸附位置的吸附能和几何构型参数的比较发现,苯在Ag(100)表面的吸附属于较强的化学作用,穴位吸附的稳定性优于桥位,顶位吸附最不稳定. 吸附的苯分子的平衡构型发生扭曲, C-C键有较大程度的伸长; C-H键的键长基本不变,但是偏离苯环平面,并背离Ag(100)表面. 在吸附过程中,电子由苯向表面银原子转移. 本文给出了详细的轨道示意图和电荷布居分析,并且与相关的实验和理论研究结果进行了比较.

A Periodical Density Functional Theory Study of Benzene Adsorption on Ag(100) Surface

The adsorption of benzene on Ag(100) surface was studied by use of the density functional theory and periodical slab model.The adsorption energy and the geometric parameters on different adsorption sites showed that the hollow site was the most favorable adsorption site,followed by the bridge one,and the top site was the least stable mode.The adsorbed benzene molecule was parallel to the Ag(100) surface,and the benzene ring was distorted.The C-C bond was elongated in comparison with the free benzene molecule while the variation of (C-H) bond length was small.The C-H bonds of benzene bent away from the benzene-ring and Ag(100) surface.The calculation results showed that the interaction between the substrate and benzene molecule was relatively strong chemisorption.The detailed orbital and the charge population analysis was given,and the calculated results were compared with the experimental and theoretical results.