物理化学学报 >> 2012, Vol. 28 >> Issue (05): 1107-1112.doi: 10.3866/PKU.WHXB201203011

理论与计算化学 上一篇    下一篇

乙炔在Ge(001)表面吸附的反应路径

范晓丽1,2, 刘燕1, 刘崇1, 刘焕明2,3   

  1. 1. 西北工业大学材料科学与工程学院, 西安 710072;
    2. 北京计算科学研究中心, 北京 100084;
    3. 成都绿色能源与绿色科技研发中心, 成都 610207
  • 收稿日期:2011-12-12 修回日期:2012-02-20 发布日期:2012-04-26
  • 通讯作者: 范晓丽, 刘焕明 E-mail:xlfan@nwpu.edu.cn; leolau@csrc.ac.cn
  • 基金资助:

    国家自然科学基金(20903075)及高等学校学科创新引智计划(111) (B08040)资助项目

Reaction Pathways of Acetylene Adsorption on the Ge(001) Surface

FAN Xiao-Li1,2, LIU Yan1, LIU Chong1, LAU Woon-Ming2,3   

  1. 1. School of Materials Science and Engineering, Northwestern Polytechnical University, Xi'an 710072, P. R. China;
    2. Beijing Computational Science Research Center, Beijing 100084, P. R. China;
    3. Chengdu Green Energy and Green Manufacturing Technology Research and Development Center, Chengdu 610207, P. R. China
  • Received:2011-12-12 Revised:2012-02-20 Published:2012-04-26
  • Contact: FAN Xiao-Li, LAU Woon-Ming E-mail:xlfan@nwpu.edu.cn; leolau@csrc.ac.cn
  • Supported by:

    The project was supported by the National Natural Science Foundation of China (20903075) and Program of Introducing Talents of Discipline to Universities, China (111 Project) (B08040).

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摘要： 采用第一性原理方法研究了乙炔分子在Ge(001)表面的吸附反应. 通过系统考察0.5 和1.0 ML覆盖度时形成di-σ和end-bridge构型的反应路径, 研究在表面形成di-σ和paired-end-bridge 构型的反应几率. 除了表面反应以外, 本文还涉及了亚表层Ge 原子参与的吸附反应, 乙炔在亚表层原子上吸附形成的亚稳态结构sub-di-σ, 是形成end-bridge 结构的第二条途径, 此反应机理对于表面吸附结构的形成起重要的作用. 与乙炔分子不同的是, 表面以下原子参与时乙烯分子的吸附反应为吸热反应. 综合热力学和动力学的分析表明,paired-end-bridge 构型是乙炔分子吸附的主要构型, 此结论解释了乙炔分子在Ge(001)表面吸附构型的实验结果. 对于乙烯和乙炔两分子在Ge(001)表面吸附的分析比较揭示了导致两者之间差异的原因.

关键词: 密度泛函理论, Ge(001)表面, 乙炔分子, 形成反应, 亚表层, 热力学, 动力学

Abstract: The adsorption reaction of acetylene on the Ge(001) surface is investigated by first-principles calculations. In order to understand the relative populations of the di-σ and paired-end-bridge structures, we calculated the adsorption reaction paths leading to their formation at 0.5 and 1.0 ML coverage. More importantly, we studied the adsorption channel involving sublayer Ge atoms by forming a metastable subdi- σ structure. This sub-di-σ structure represents second reaction pathway that results in the end-bridge structure, which plays an important role in the formation of the adsorption configurations. In contrast to C2H2, the adsorption of C2H4 on the Ge(001) surface involving subsurface Ge atoms, is endothermic. Our calculations show from both kinetic and thermodynamic standpoints that the paired-end-bridge structure is the primary adsorption configuration that explains the experimental observations. Our work also helps to understand the fundamental differences between the adsorption of C2H2 and C2H4 on the Ge(001) surface.

Key words: Density functional theory, Ge(001) surface, Acetylene molecule, Formation reaction, Sublayer, Thermodynamics, Kinetics