中文摘要：

采用完全活化空间自洽场（CASSCF）方法及内收缩多参考组态相互作用（MRCI）理论,在键长0.07345到1.65345nm的范围内,对BeO分子基态（X1Σ＋）的势能曲线进行了理论研究,通过Molcas程序拟合出了光谱常数De,Re,ωe,ωeχe,Be和αe.并通过求解双原子分子核运动的径向Schr dinger方程,找到了J=0时该分子基态存在的全部63个振动态.针对每一振动态,第一次计算了其振动能级,经典转折点,惯性转动常数Bυ和离心畸变常数Dυ.与现有的实验及其他理论相比较,我们发现本文的光谱参数和分子常数结果更准确.

英文摘要：

The potential energy curve（PEC） of BeO molecule are investigated using the complete active space self-consistent field（CASSCF） method followed by the highly accurate valence internally contracted multireference configuration interaction（MRCI） approach over the internuclear separation range from 0.07345 to 1.65345nm.Using the PEC of BeO molecule obtained,with the help of MOLCAS 7.4 program package,the spectroscopic parameters De,Re,ωe,ωeχe,Be and αe are obtained.With the PEC of X1Σ＋ determined,a total of 63 vibrational states have been predicted for the first time by numerically solving the radial Schrdinger equation.For each vibrational state,the complete vibrational levels,classical turning points,inertial rotation and centrifugal distortion constants are determined for the first time.Comparing with the available experiments and other theories,the research finds that the present spectroscopic parameter and molecular constant results are more accurate and complete than previous theoretical investigations.