苯在CuCl(111)表面吸附的密度泛函理论研究

Density Functional Theory Study of Benzene Adsorption on CuCl(111) Surface

采用量子化学的密度泛函理论方法,探讨了苯分子在CuCl(111)表面上不同覆盖度下不同吸附位上的平行吸附行为.计算结果表明,随覆盖度的减小,吸附作用增强,Cl位上的吸附是稳定的吸附模式,在低覆盖度下吸附能约为74 kJ/mol,在顶位和穴位上的吸附属于较弱的物理吸附.同时对吸附前后的电子布居和态密度进行了分析.吸附过程中,苯分子的π电子向底物转移,同时Cu的3d轨道的电子反馈给苯的反键π轨道.

The adsorption of benzene on CuCI（111） surface has been studied by density functional theory calculation with the GGA Perdew-Wang method. The calculated results indicate that benzene adsorption on surface Cl site is the most favorable. The smaller the coverage is, the more stable the adsorption is. The predicted adsorption energy for benzene adsorption on Cl site is 74 kJ/mol, in fair agreement with the experimental results. The benzene adsorption on top and hollow sites is physical adsorption. The density of states and the charge population before and after the adsorption have also been analyzed. The calculated results show the back donation of Cu 3d electrons to the π^＊ anti-bonding orbital of benzene, which weakens the aromatic bond.