物理化学学报 >> 2004, Vol. 20 >> Issue (11): 1380-1384.doi: 10.3866/PKU.WHXB20041119

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PdH2、YH2分子的结构与势能函数

倪羽;蒋刚;朱正和;孙颖;高涛;王红艳   

  1. 四川大学原子分子物理研究所,成都 610065;中国工程物理研究院,绵阳 621900; 四川师范大学化学学院,成都 610066
  • 收稿日期:2004-04-22 修回日期:2004-06-07 发布日期:2004-11-15
  • 通讯作者: 蒋刚 E-mail:gjiang@scu.edu.cn

Structures and Potential Energy Functions of PdH2 and YH2 Molecules

Ni Yu;Jiang Gang;Zhu Zheng-He;Sun Ying;Gao Tao;Wang Hong-Yan   

  1. Institute of Atomic and Molecular Physics, Sichuan University, Chengdu 610065; China Academy of Engineering Physics, Mianyang 621900; Department of Chemistry, Sichuan Normal University, Chengdu 610066
  • Received:2004-04-22 Revised:2004-06-07 Published:2004-11-15
  • Contact: Jiang Gang E-mail:gjiang@scu.edu.cn

摘要: 用密度泛函理论的B3LYP方法,对钯和钇原子采用SDD收缩价基函数,氢原子采用6-311++G**全电子基函数,对PdH2和YH2体系的结构进行优化计算,得到PdH2分子最稳态为C2v构型,电子组态为1A1,平衡核间距RPdH=0.1692 nm,键角∠HPdH=29.4°,离解能De=5.5212 eV,基态简正振动频率:ν1(b2)=1470.1 cm-1、ν2(a1)=1007.9 cm-1、ν3(a1)=2907.0 cm-1.YH2分子最稳态也为C2v构型,电子组态2A1,RYH=0.1962 nm,∠HYH=114.3°,De=5.6691 eV,基态简正振动频率:ν1(b2)=1457.9 cm-1、ν2(a1)=476.0 cm-1、ν3(a1)=1506.3 cm-1.由微观过程的可逆性原理分析了分子的可能离解极限.并用多体项展式理论方法分别导出基态PdH2和YH2分子的势能函数,其等值势能面图准确地再现了PdH2和YH2分子的结构特征和离解能,由此讨论了Pd + H2和Y + H2分子反应的势能面静态特征.

关键词: PdH2, YH2, 分子结构, 势能函数

Abstract: Density functional(B3LYP) method has been used to optimize the possible structures of PdH2 and YH2 molecules by contracted valence basis set(SDD) for Pd and Y atoms, the 6-311++G** basis set for H atom. The results show that the ground state of PdH2 molecule is C2v symmetry and X 1A1 state. The parameters of structure and the harmonic frequencies are RPdH=0.1692 nm, ∠HPdH=29.4°, De=5.5212 eV and ν1=1470.1 cm-1,ν2=1007.9 cm-1,ν3=2907.0 cm-1 respectively. The results also show that the ground state of YH2 molecule is C2v symmetry and X 2A1 state. The parameters of structure and the harmonic frequencies are RYH=0.1962 nm,∠HYH=114.3°, De=5.6691 eV and ν1=1457.9 cm-1,ν2=475.9 cm-1,ν3=1506.3 cm-1 respectively. The potential energy functions of PdH2 and YH2 have been derived from the normal equation fitting and the many-body expansion theory which is successfully used for describing the equilibrium geometry of PdH2 and YH2.Molecular reaction kinetics of Pd + H2 and Y + H2 based on this potential energy function is discussed briefly.

Key words: PdH2, YH2, Molecular structure, Potential energy function