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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。
Based on RCEP (Relativistic Compact Effective Poten-tial) method, the ground state of LaH2 molecule is C2v (X2A1) at the QCISD level with ∠HLaH = 124.4 ° and equilibrium nuclear spacing Re = 2 .1945 A and the dissociation energy De = 5.599 eV, and the resonance frequency was calculated: v1 = 1216.521 cm-1, V2 = 1087.417 cm-1 and v3 = 2156.9572 cm-1. Based on this, the analytic potential energy function of ground state LaH2 is deduced using the multi-body expansive theory. The potential energy surface accurately reproduces the equilibrium structure of LaH2 (C2v). The H + LaH reaction and La + H2 The results show that there is a saddle point with an energy barrier of 1.6eV on the La + H2 channel, while the H + LaH reaction channel is without threshold energy.