PdYH分子的结构与势能函数  

Structures and Potential Energy Functions of PdYH Molecule

作　　者：倪羽[1] 蒋刚[1] 朱正和[1] 孙颖[2] 

机构地区：[1]四川大学原子分子物理研究所 [2]中国工程物理研究院,绵阳621900

出　　处：《化学学报》2005年第8期764-768,共5页Acta Chimica Sinica

基　　金：国家自然科学基金(No. 10176021)资助项目.

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PdY 和PdYH 体系的结构进行优化. 计算表明: PdY 分子的几何构型为C∞v, 其基态为X2Σ+态, 键长R=0.24168nm, 离解能为De=2.8261 eV, 谐振频率ωe=254.0656 cm-1, 并拟合得到Murrell-Sorbie 势能函数; PdYH 分子最稳态为Cs 构型, 电子组态为A', 平衡核间距RPdY=0.24281 nm, RYH=0.19824 nm, 键角∠PdYH=116.7157°, 离解能De=15.6146 eV, 基态简正振动频率: 对称伸缩振动频率ν1 (a')=348.2909 cm-1, 弯曲振动频率ν2 (a')=243.3382 cm-1, 反对称伸缩振动频率ν3 (a')=1442.2695 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PdY 和PdYH 分子的势能函数, 其等值势能面图准确地再现了PdY 和PdYH 分子的结构特征和离解能, 由此讨论了Pd+Y+H 分子反应的势能面静态特征.Density functional method (B3LYP) has been used to optimize the possible structures of PdY and PdYH molecules by contracted valence basis set (SDD) for Pd and Y atoms and the 6-311 + + G** basis set for H atom. The results show that the ground states of PdY and PdYH molecules are X(2)Sigma(+) and X(1)A(1) states, respectively. The equilibrium geometry R = 0.24168 nm, dissociation energy D-e = 2.8261 eV, and spectral constants omega(e) = 254.0656 and omega(e)x(e) = 0.60391 cm(-1) of PdY (C-infinity nu) molecule have been obtained, respectively. For PdYH (C-s) molecule, the equilibrium geometry, dissociation energy and harmonic frequency were calculated, and the results show that R-PdY = 0.24281 nm, R-YH = 0.19824 nm, angle PdYH = 116.7157 degrees and D-e = 5.6146 eV, and nu(1) (alpha') = 348.2909 cm(-1), nu(2) (alpha') = 243.3382 cm(-1), nu(3) (alpha') = 1442.2695 cm(-1), respectively. Analytical potential energy function for the PdYH has been derived for the first time using many-body expansion method, which was successfully used for describing the equilibrium geometry of PdYH. Molecular reaction kinetics of Pd((1)Sg) + Y((2)Dg) + H((2)Sg) based on this potential energy function is being studied under way.

关 键 词：密度泛函理论 钯 钇 收缩价基函数 全电子基函数 势能函数 分子结构 计算方法 

分 类 号：O641[理学—物理化学]