BeH_2(~1Σ_g^+)与H_2S(~1A_1)分子的结构与解析势能函数  

The structure and potential energy function of BeH_2(~1Σ_g^+) and H_2S(~1A_1) molecules

作　　者：令狐荣锋[1,2] 李劲[1,3] 吕兵[1,2] 徐梅[2] 杨向东[1] 

机构地区：[1]四川大学原子与分子物理研究所,成都610065 [2]贵州师范大学理学院,贵阳550001 [3]海南大学材料与化工学院,海口570228

出　　处：《物理学报》2009年第1期185-192,共8页Acta Physica Sinica

基　　金：国家自然科学基金(批准号:10574096);高等学校博士点专项科研基金(批准号:20050610010);贵州省教育厅自然科学重点项目(批准号:2005105);贵州省优秀科技教育人才省长基金(批准号:黔省专合字(2006)113号)资助的课题~~

摘　　要：运用单双取代二次组态相关(QCISD)方法,在6-311++G(3df,3pd)基组水平上,对BeH2和H2S分子的结构进行了优化计算,得到基态BeH2分子的稳定结构为D∞h构型,电子态为X～1Σg+,平衡核间距RBeH=0.13268nm,RHH=0.26536nm,键角∠HBeH=180.0°、离解能De=6.283383eV和基态振动频率ν1,ν2,ν3;同样方法得到了基态H2S分子的稳定结构为C2v构型,电子态为～X1A1,得到了平衡核间距RHS=0.13357nm,RHH=0.193155nm,键角∠HSH=92.6166°、离解能De=11.45901eV和基态振动频率ν1,ν2,ν3;用多体项展式理论推导了基态BeH2和H2S分子的解析势能函数,其等值势能图准确再现了基态BeH2和H2S分子的结构特征及其势阱深度与位置.Quadratic configuration interaction method including single and double substitutions has been used to optimize the possible structures of BeH2 and H2S molecules with the 6-311＋＋g（3df,3pd） basis set.The results show that the ground state of BeH2 molecule is of D∞h symmetry and is in the [AKX～]1Σ＋g state,the ground state of H2S molecule is of C2v symmetry and in the [AKX～]1A1 state.The equilibrium geometry,dissociation energy,harmonic frequencies and force constants have been calculated.The potential energy functions of BeH2 and H2S have been derived by using the many-body expansion theory.The potential energy functions describe correctly the configurations and the dissociation energies of the two ground-state molecules.

关 键 词：BeH2 H2S MURRELL-SORBIE函数 多体项展式理论 解析势能函数 

分 类 号：O561.1[理学—原子与分子物理] O562.1[理学—物理]