~7LiH分子X^1Σ^+态的平衡几何、谐振频率、离解能及其解析势能函数  

The Accurate Equilibrium Geometry,Harmonic Vibrational Frequency, Dissociation Energy and Analytical Potential Energy Function for the State X^1Σ^+ of ~7LiH Molecule

作　　者：施德恒[1] 戴启润[1] 王栋臣[1] 王林[1] 张东玲[1] 熊宝库[1] 

机构地区：[1]信阳师范学院物理电子工程学院,河南信阳464000

出　　处：《信阳师范学院学报（自然科学版）》2006年第2期144-147,152,共5页Journal of Xinyang Normal University(Natural Science Edition)

基　　金：国家自然科学基金项目(10574039);河南省自然科学基金项目(0511014300);河南省教育厅自然科学基金项目(2006140008)

摘　　要：利用分子反应静力学的原理,确定了7L iH分子X1Σ+态的合理离解极限;使用HF、QC ISD、QC ISD(T)、B3LYP和B3P86等方法,6-311G、6-311G(d,p)、6-311G(3df,3pd)、D95V(d,p)和D95V(3df,3dp)等基组,对7LiH分子X1Σ+态的平衡核间距、谐振频率和离解能进行了优化计算,且将计算结果(平衡核间距0.160 9 nm、谐振频率1 390.51 cm-1、离解能2.474 eV)与实验结果(平衡核间距0.159 6 nm、谐振频率1 405.7cm-1、离解能2.515 eV)进行了比较,得出了包含单、双取代并加入三重激发贡献的QC ISD(T)方法为最优方法、基组6-311G(3df,3pd)为最优基组的结论.在QC ISD(T)/6-311G(3df,3pd)理论水平,对7LiH分子的X1Σ+态进行了单点能扫描,并用最小二乘法拟合出了其解析势能函数;从拟合出的解析势能函数出发,计算出了X1Σ+态的光谱常数Be,αe和ωeeχ(其值分别为7.379 cm-1、0.197 6 cm-1和21.697 cm-1),以及二阶、三阶和四阶力常数f2、f3和f4(其值分别为106.37 aJ.nm-2、-3 650.4 aJ.nm-3和112 176.2 aJ.nm-4).The reasonable dissociation limit of the X^1∑^＋ state 7 LiH molecule is attained by using the molecular reaction static theory. The equilibrium separation of 0. 160 9 nm, the harmonic vibrational frequency of 1 390.51 cm^-1 and the dissociation energy of 2.474 eV about this state are accurately calculated by using such methods as HF,QCISD,QCISD（T） ,B3LYP and B3P86 with the basis sets 6-311G,6-311G（d,p） ,6-311G（3df, 3 pd）, D95 V （ d, p） and D95 V （3 dr,3 pd）. Comparing the attained results with the experiments, the conclusion is gained that the QCISD（T）/6-311G（3df,3pd） is the most suitable for the ground-state energy calculation of ^7LiH molecule. The whole potential energy curve for this state is further scanned at the QCISD（T）/6-311G （3dr, 3pd） theory level,then has a least squares fitted to the analytic Murrell-Sorbie function form,and last the spectroscopy data （Be = 7. 379 cm^-1, αe = 0. 197 6 cm^-1 and ωeXe = 21. 697 cm^-1 ） and force constants （f2 = 106.37 aJ · nm^-2, f3 =-3 650.4 aJ · nm^-3 and f4 =112 176.2 aJ · nm^-4） are calculated.

关 键 词：原子与分子物理 原子分子碰撞 电子结构 解析势函数 ^7H Boee-Einstein凝聚 

分 类 号：O561.1[理学—原子与分子物理]