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本文分别用原子簇模型(CM)和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Ag_6O_2为模型体系,对O_2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~1A_1和~3A_2,它们分别对应在[110]槽位吸附的过氧分子O_2~(2-)和在[001]方向吸附的超氧分子O_2,理论优化的吸附构型和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.
In this paper, the chemisorption configurations, adsorption states and adsorption energies of molecular oxygen on Ag (110) surface have been studied by ab initio calculation using atomic cluster model (CM) and immersion in the cluster model of adsorbed atoms (DAM) Model system, the chemisorption of O2 on the long bridge (LB) site of Ag (110) surface shows that the two lowest energy states are ~ 1A_1 and ~ 3A_2, which correspond to the oxygen molecules adsorbed on the [110] ~ (2-) and superoxide molecule O_2 adsorbed in the [001] direction, the theoretically optimized adsorption conformation is in good agreement with the experimental measurement and analysis results. Since CM method ignores the influence of metal bulk, the adsorption energy obtained is significantly lower than the experimental value (Even negative), while the DAM method yields positive adsorption energy, which is quite close to the experimental value of 38.9 kJ / mol, of which the adsorption at [110] is more stable.