LiBr分子基态光谱常数和分子常数研究（英文）

Theoretical investigation on spectroscopic parameters and molecular constants of Li Br( X^1∑^+) molecule

采用高精度的量子化学从头计算多参考组态相互作用方法(MRCI)和相关一致基,计算了Li Br分子基态的光谱常数(Re,ωeand De)和势能曲线.为获得更准确的结果,计算中还考虑了二阶Douglas-KrollHess相对论修正对Li Br分子基态的平衡键长、谐振频率和离解能影响.将计算得到的势能曲线拟合为Murrell-Sorbie解析势能函数形式,并进一步计算得到Li Br分子基态的其它光谱常数(ωeχe,αe,Beand 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 Br分子基态的全部振动态.还计算了每一个振动态的振动能级、经典转折点和惯性转动常数,这些结果与已有的实验值一致.

Ab initio calculations using multireference configuration interaction （MRCI） theory in combination with a series of correlation-consistent basis sets are used to determine the accurate spectroscopic parameters （Re, toe and Do） and potential energy curves for the ground state of diatomic molecules LiBr. We discuss the Douglas- Kroll-Hess 2^nd order scalar relativistic effects on bond lengths, harmonic frequencies and dissociation energies of LiBr. The potential energy curves are all fitted to the Murrell-Sorbie function, which are used to accurately reproduce the spectroscopic parameters such as ωeXe, αe, Be and D0, which are in excellent agreement with experimental values. Based on the analytical potential energy function, the total vibrational manifolds of LiBr are calculated by numerically solving the radical Schrodinger equation of nuclear motion. For each vibrational state, the vibrational level, classical turning points and inertial rotation constants are obtained, which are in agreement with the available experiments.