LiI分子基态的势能函数与光谱常数的研究

Research on Potential Energy Function and Spectroscopic Constants of the Ground States of LiI

采用多参考组态相互作用方法(MRCI)结合Dunning等的相关一致基,计算了Li I分子基态的势能曲线和光谱常数(Re,ωeand De)。为获得更准确的结果,计算中还考虑了相对论修正对Li I分子基态的平衡键长、谐振频率和离解能影响。在二阶Douglas-Kroll哈密顿近似下计算得到势能曲线并将其拟合为Murrell-Sorbie解析势能函数形式,并进一步计算得到Li I分子基态的其它光谱常数(ωeχe,αe,Be和D0)。比较发现它们与实验值符合的非常好。通过求解核运动径向Schr?dinger方程,找到了Li I分子基态的全部振动态。还计算了前20个振动态的振动能级、经典转折点、惯性转动常数和离心畸变常数。

Using multireference configuration interaction(MRCI)theory in combination with a series ofcorrelation-consistent basis sets are used to determine the accurate spectroscopic parameters(Re,ωe andDe)and potential energy curves for the ground state of diatomic molecules LiI.We discuss the Douglas-Kroll-Hess2nd order scalar relativistic effects on bond lengths,harmonic frequencies and dissociationenergies of LiI.The potential energy curves are all fitted to the Murrell-Sorbie function,which are usedto accurately reproduce the spectroscopic parameters such asωeχe,αe,Be and D0,which are in excellentagreement with experimental values.Based on the analytical potential energy function,the totalvibrational manifolds of LiI are calculated by numerically solving the radical Schr?dinger equation ofnuclear motion.For the first20vibrational state,the vibrational level,classical turning points andinertial rotation constants are obtained.