物理化学学报 >> 2009, Vol. 25 >> Issue (06): 1195-1200.doi: 10.3866/PKU.WHXB20090627

研究论文 上一篇    下一篇

CO与Pdn(n=1-8)团簇的相互作用

葛桂贤, 唐光辉, 井群, 罗有华   

  1. 石河子大学师范学院物理系生态物理重点实验室, 新疆 石河子 832003|华东理工大学理学院,上海 200237|河南大学物理与电子学院, 理论物理研究所, 河南 开封 475004
  • 收稿日期:2008-12-24 修回日期:2009-02-28 发布日期:2009-06-05
  • 通讯作者: 葛桂贤 E-mail:geguixian@126.com

Interaction of CO with PalladiumClusters Pdn (n=1-8)

GE Gui-Xian, TANG Guang-Hui, JING Qun, LUO You-Hua   

  1. Key Laboratory of Ecophysics, Department of Physics, Normal College, Shihezi University, |Shihezi 832003, The Xinjiang Uygur Autonomous Region, P. R. China|School of Science, East China University of Science and Technology, Shanghai 200237, P. R. China|Institute for Theoretical Physics, School of Physics and Electronics, Henan University, Kaifeng 475004, Henan Province, P. R. China
  • Received:2008-12-24 Revised:2009-02-28 Published:2009-06-05
  • Contact: GE Gui-Xian E-mail:geguixian@126.com

摘要:

采用密度泛函理论对CO与钯团簇的相互作用进行了系统研究. 结果表明, PdnCO(n=1-8)体系的最低能量结构是在Pdn(n=1-8)团簇最低能量结构或亚稳态结构的基础上吸附CO生长而成; CO的吸附以端位吸附为主, 其吸附没有改变Pdn团簇的结构; CO分子在Pdn团簇表面发生的是非解离性吸附. 与优化的CO键长(0.1166 nm)相比, 除了n=2, 团簇PdnCO的C—O键长为0.1167-0.1168 nm, 吸附后C—O键长变化较小, CO分子被活化程度较小. 电荷集居数分析表明, CO的吸附对Pdn团簇的影响比较小; 二阶能量差分表明, n=4,6的团簇是相对稳定的团簇.

关键词: PdnCO和Pdn团簇, 密度泛函理论, 几何结构, 电子性质

Abstract:

Adsorption of CO onto Pdn (n=1-8) clusters was systematically investigated using density functional theory. Results indicate that the lowest energy structures of PdnCO are still generated when CO is adsorbed onto Pdn clusters. We found that among the molecular adsorption states, a weakly bound state with end-on type geometry is the most energetically favorable. The lowest energy structures of Pdn clusters are not changed by adsorbing CO molecules. Chemisorption of CO onto Pdn cluster surfaces is a non-dissociative adsorption process. An increased theoretical CO bond length of 0.1167-0.1168 nm in PdnCO cluster (compared to 0.1166 nm in free CO molecule) indicates a small activation for the CO bond except for the case where n=2. Natural bond orbital analysis shows that the interaction between a Pd atom and a CO molecule is small. The second-order energy difference shows that Pd4CO and Pd6CO clusters have enhanced stabilities.

Key words: PdnCO and Pdn clusters, Density functional theory, Geometry, Electronic property

MSC2000: 

  • O641