CO分子在TiC(001)表面上的吸附构型与电子结构  

Geometries and Electronic Structures for the Adsorption of CO Molecule on TiC(001) Surface

作　　者：干琴芳[1] 倪碧莲[2] 李奕[1] 丁开宁[1] 章永凡[1] 

机构地区：[1]福州大学化学系,福州350002 [2]福建医科大学药学院基础化学系,福州350004

出　　处：《物理化学学报》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

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.

关 键 词：过渡金属碳化物 表面吸附 能带结构 密度泛函理论 

分 类 号：O641.1[理学—物理化学]