周期性密度泛函理论研究氯气在CuCl(111)表面上的吸附与解离

A DFT Study on the Adsorption and Dissociation of Cl_2 on CuCl(111) Surface

运用广义梯度密度泛函理论(Generalized Gradient Approximation,GGA)的PBE(Perdew-Burke-Ernzerh)方法结合周期性平板模型,研究了氯气分子和氯原子在CuCl(111)表面上的吸附。通过对不同吸附位和不同单层覆盖度下的吸附能和几何构型参数的计算和比较发现:氯气分子在CuCl(111)表面的吸附为解离吸附;单层覆盖度为0.50时的吸附构型为稳定的吸附构型;氯气分子平行吸附在CuCl(111)表面时最稳定,吸附能最大,达364.5kJ·mol^(-1);伸缩振动频率的计算结果表明,吸附后的氯气分子的伸缩振动频率与自由氯气分子的伸缩振动频率相比,都发生了红移;布居分析结果表明整个吸附体系发生了由Cu原子向氯气分子的电荷转移。氯原子吸附的计算结果显示氯原子以穴位稳定的吸附在CuCl(111)表面。

The adsorption of Cl2 molecule on CuCl（lll） surface has been studied with periodic slab model by Perdew-Burke-Ernzerh （PBE） approach of the generalized gradient approximation （GGA） within the framework of density functional theory （DFT）. The adsorption models under different coverage of CuCl （111） surface and the adsorption over various adsorption sites （top, hollow, bridge, parallel, and Cl site） have been considered. The optimized results indicate that the adsorption is very stable when the coverage is set to 0.50 monolayer and the most stable site is parallel. The Cl-Cl stretching vibrational frequencies are significantly red-shifted. The population analysis indicates that the charges transfer from Cu atoms to Cl2 molecule. The favorite adsorption occurs at the hollow site for Cl atoms adsorption on CuCl（111） surface.