NiO(001)表面吸附CO的从头算研究

用量子化学B3LYP方法,以外加点电荷来封闭边界效应的簇为模型,计算了CO在NiO(001)面上不同吸附位置的吸附情况,并计算了振动频率。结果表明:1) CO的最佳吸附方式为C端垂直吸附在Ni位;2)吸附后CO间的振动频率蓝移13 cm-1;3)在O空缺、边和角等位置的吸附不如在完整表面的吸附稳定,这些均与实验结果一致。吸附后CO把主要起反键作用的C2s电子给予簇表面,使得吸附后CO键级加大,导致吸附后振动频率蓝移。并比较了Gaussian98 和Crystal98的计算结果,两者的结果能较好地符合。

Ab initio Study on Adsorption of CO on NiO (001) Surface

We report herein the results of ab initio cluster model calculation of the interaction of CO with NiO(001) surface, and the clusters used are embedded in the point charge to remove the boundary effect. The results show: 1) the optimum adsorption manner is that CO adsorbs in the Ni site perpendicularly with its C-termination; 2) after adsorption the CO vibration frequency shifts towards 13 cm-1 higher than that of free molecule; 3) adsorption in O-vacancy, edge and angle are more unstable than that in perfect surface; these results are all consistent with those from experiment. In studying the effect of (001) surface on CO molecule after adsorption, we find that CO gives the C2s electron which is mainly anti-bond in CO to the (001) surface and the vibration frequency of CO shifts towards higher wave number after adsorption. A comparison between the calculated results of Gaussian98 and Crystal98 has been carried, finding these two results are basically compatible.