分子态氧在Ag(110)面上的吸附构型、吸附态和吸附能的CM和DAM从头算研究

本文分别用原子簇模型(CM)浸入吸附原子簇模型(DAM)的从头算方法, 研究了分子态氧在Ag(110)面上的化学吸附构型, 吸附态和吸附能。以Ag6O2为模型体系,对O2在Ag(110)表面长桥位(LB)化学吸附的研究表明: 二个最低能态是^1A1和^3A2,它们分别对应在110]槽位吸附的过氧分子O2^2^-和在001]方向吸附的超氧分子O2^-, 理论优化的吸附构型的实验测量分析结果非常一致。由于CM方法忽略了金属本体的影响, 所得吸附能明显低于实验值(甚至是负值), 而DAM方法得到正的吸附能, 且相当接近于实验值38.9kJ/mol, 其中110]槽位吸附更为稳定。

An ab initio study of adsorption geometries, states and energies of molecular oxygen on Ag(110) surface with the CM and DAM method

Molecular oxygen chemisorption on Ag(110) surface at long bridge (LB) site has beenstudied theoretically by use of cluster model (CM) and dipped adcluster model (DAM)for Ag6O2 system. Two low-lying states, ^1A1 and ^3A2, are obtained. The ^1A1 state corresponds th the O2^2^- species adsorption along 110] trough, while the ^3A2 state to the O2^- species along 001] direction. For the CM method, the calculated binding energies of the two states are much lower than the experimental data (even negative). With the DAM method, the adsorption system is stabilized to produce positive binding energies, which are remarkable close to the experimental value of 38.8 kJ/mol, and the 110] trough geometry is obviously preferred. The optimized adsorption geometries are in good agreement with the experimental results.