摘要
采用第一性原理方法和平板模型对CO分子在TiC(001)表面的吸附构型和电子结构进行了详细研究.结果表明,CO分子倾向于采用C端吸附在表层Ti原子上方.对于该吸附方式,计算得到的吸附能、CO各电子态所处能级位置以及C—O键伸缩振动频率的红移值均与实验观测结果相吻合.由能带结构和Mülliken布居分析结果可知,当采用C端吸附时,CO的5!和2"*态受到底物影响最为显著,尤其是C端的桥位吸附方式.此外,还进一步对底物表面态在CO吸附过程中的作用进行了探讨.
Using the first-principles method, the configurations and electronic structures for the adsorption of CO molecule on TIC（001） surface were investigated in details with a slab model. Our results showed that the CO molecule tended to occupy the atop site of the surface Ti atom through its C ending, and the predicted adsorption energy, the positions of CO valence levels and the red shift of C--O stretching frequency were in agreement with the experimental observations. By analyzing the band structures and Mülliken population, when CO molecule was adsorbed by C ending, the compositions and energy levels of the corresponding 5σ and 2π^＊ states changed obviously with respect to CO in gas-phase, especially for the case that CO sited at the bridge site between two neighbor Ti atoms. Furthermore, the role of the surface state during the CO adsorption was discussed.
出处
《物理化学学报》
SCIE
CAS
CSCD
北大核心
2008年第10期1850-1858,共9页
Acta Physico-Chimica Sinica
基金
国家自然科学基金(20673019,20773024)
教育部博士点基金(20060386001)
福建省自然科学基金(Z0513005,U0650012)资助项目
关键词
过渡金属碳化物
表面吸附
能带结构
密度泛函理论
Transition metal carbides
Surface adsorption
Band structure
Density functional theory
