With the accurate ab initio method, the adsorption and dissociation process of H2 molecule on Al−7 cluster anion are investigated. The stable structures of molecular adsorption and dissociative adsorption are confirmed. The photoelectron spectra of different struc-tures are further analyzed. The calculations indicate that the adsorption of H2 on Al−7 is weak physical adsorption with the adsorption energy about 0.02 eV. The investigation of the dissociation process shows that the energy barrier of dissociation is about 0.75 eV. The densities of states of the Al−7 cluster and the dissociative adsorption complex Al7H−2 are in good agreement with those obtained by the photoelectron spectroscopy. It suggests that H2 can be dissociated when it is absorbed on Al−7 anions produced by laser ablation.% 利用高精度从头计算方法研究了H2分子在Al−7阴离子团簇上的吸附及解离过程，确定了分子吸附及解离吸附的稳定结构，并分析了各结构的光电子能谱.计算表明H2在Al−7上为弱的物理吸附，吸附能约为0.02 eV；解离过程的能垒约为0.75 eV.对团簇及解离吸附结构的态密度与实验得到的光电子能谱的比较表明二者能够很好地符合，确定H2与激光烧蚀产生的团簇直接反应时能在Al−7上发生解离.
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