| 周期性密度泛函理论研究NO在Cu2O(111)表面上的吸附 |
| A DFT Study on the Chemisorption of NO on Cu2O(111) Surface |
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| 摘要: 运用广义梯度密度泛函理论(GGA)的PBE方法结合周期平板模型，在DND基组下，研究了NO以N端和O端两种吸附取向在Cu2O(111)非极性表面上的吸附。通过对不同吸附位置的吸附能和几何构型参数的计算和比较发现：表面上配位不饱和的铜离子(CuCUS)为活性吸附位；NO的N端吸附比O端吸附更为有利，N端吸附时吸附能可达到113.5 kJ·mol-1，而O端情况下只有39.7 kJ·mol-1；NO倾斜吸附在Cu2O(111)表面上，O端吸附时倾斜度更大。在两种吸附取向情况下，N-O键的伸缩振动频率都发生了较大的红移，N端吸附情况下红移150 cm-1，O端时红移330 cm-1。前线轨道分析表明，Cu与NO间的吸附作用主要是Cu的d轨道和NO的π*轨道间的相互作用。表面弛豫的计算表明，Cu2O(111)面的弛豫对O端吸附方式产生较大影响，考虑表面弛豫时O端吸附为很弱的化学吸附(吸附能为39.7 kJ·mol-1)，而没有考虑弛豫时吸附能为60.5 kJ·mol-1。 |
| 关键词: 密度泛函理论 周期平板模型 NO 吸附 Cu2O(111)非极性表面 |
| 基金项目: |
| Abstract: The adsorption of NO molecule on Cu2O(111) non-polar surface has been studied with periodic slab model by Perdew-Burke-Ernzerh approach of GGA within the framework of density functional theory. Two molecular orientations, N- and O-down, over different adsorption sites, CuCUS, CuCSA, OSUF and OSUB of the Cu2O(111) surface have been considered. The optimized results indicate that the N-down adsorption models are sable than the O-down ones. The adsorption energy for the N-down mode over CuCUS site is 113.5 kJ·mol-1 while the corresponding value for the latter mode is 39.7 kJ·mol-1. Upon adsorption on the Cu+ cation, the NO molecules forms a bent Cu+-NO bond, and the tilted angles are different at the two orientations. The N-O stretching frequencies for both orientations are significantly red-shifted upon coordination. The frontier molecular orbitals analysis indicates that, for N-down and O-down orientation, the interaction between the adsorbed molecule and the substrate mainly arises from the anti-bonding π orbital of NO and the d orbital of copper atom. Moreover, the relaxation should be considered because of the effects of the geometry of Cu2O(111) surface upon the adsorption geometries and the binding energies of O-down adsorption. |
| Keywords: density functional theory periodic slab model nitrogen oxide adsorption Cu2O(111) non-polar surface |
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| 孙宝珍,陈文凯,刘书红,曹梅娟,陆春海,许莹.周期性密度泛函理论研究NO在Cu2O(111)表面上的吸附[J].无机化学学报,2006,22(7):1215-1221. |
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