物理化学学报 >> 2008, Vol. 24 >> Issue (10): 1850-1858.doi: 10.3866/PKU.WHXB20081019

研究论文 上一篇    下一篇

CO分子在TiC(001)表面上的吸附构型与电子结构

干琴芳; 倪碧莲; 李奕; 丁开宁; 章永凡   

  1. 福州大学化学系, 福州 350002; 福建医科大学药学院基础化学系, 福州 350004
  • 收稿日期:2008-04-07 修回日期:2008-06-04 发布日期:2008-10-08
  • 通讯作者: 章永凡 E-mail:zhangyf@fzu.edu.cn

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

GAN Qin-Fang; NI Bi-Lian; LI Yi; DING Kai-Ning; ZHANG Yong-Fan   

  1. Department of Chemistry, Fuzhou University, Fuzhou 350002, P. R. China; Department of Fundamental Chemistry, College of Pharmacy, Fujian Medical University, Fuzhou 350004, P. R. China
  • Received:2008-04-07 Revised:2008-06-04 Published:2008-10-08
  • Contact: ZHANG Yong-Fan E-mail:zhangyf@fzu.edu.cn

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Mvlliken布居分析结果可知, 当采用C端吸附时, CO的5σ和2π鄢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.

关键词: 过渡金属碳化物, 表面吸附, 能带结构, 密度泛函理论

Abstract: 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 Mvlliken 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.

Key words: Transition metal carbides, Surface adsorption, Band structure, Density functional theory

MSC2000: 

  • O641