摘要
在ＱＣＩＳＤ水平上基于相对论紧致有效势（ＲＣＥＰ：Ｒｅｌａｔｉｖｉｓｔｉｃ Ｃｏｍｐａｃｔ Ｅｆｆｅｃｔｉｖｅ Ｐｏｔｅｎ－ｔｉａｌ）方法优化出ＬａＨ２分子的基态为Ｃ２ｖ（Ｘ２Ａ１）构型，其∠ＨＬａＨ＝１２４．４°、平衡核间距Ｒｅ＝２．１９４５ Ａ和离解能Ｄｅ＝５．５９９ｅＶ，并计算出谐振频率：ｖ１＝１２１６．５２１ ｃｍ－１、Ｖ２＝１０８７．４１７ｃｍ－１和ｖ３＝２１５６．９５７２ｃｍ－１。在此基础上，应用多体项展式理论，导出了基态ＬａＨ２的分析势能函数，该势能表面准确地再现了ＬａＨ２（Ｃ２ｖ）平衡结构，并根据势能函数等值图讨论了Ｈ＋ＬａＨ反应和Ｌａ ＋Ｈ２反应的势能面静态特征，结果表明在Ｌａ＋Ｈ２通道上存一个能垒为 １．６ｅＶ的鞍点，而 Ｈ＋ＬａＨ反应通道是无阈能的。
The present work has derived analytical potential energy function for the ground state (C2v, X2A1) of LaH2. In the first place, the electronic state and it's reasonable dissociation limits are correctly determined based on Atomic and Molecular Reaction Statics (AMRS), and then, using the relativistic compact effective potential (RCEP) for La, the equilibrium geometry, dissociation energy and harmonic frequencies for LaH2 have been calculated by ab initio method, the reasults show that RLaH = 2.1945 A ,∠HLaH = 124.4° and De= 5.599 eV, and v1, v2 and v3 are 1216.521, 1087.417 and 2156.957cm-1, recpectively. Molecular reaction kinetic of La+H2 and La+H based on this potential energy function is under the way.
基金
中国工程物理研究院材料研究所基金课题!(06)1998
关键词
势能函数
基态
贮氢合金
结构
LaH2, Many-body expansion method, Analytical potential energy function
