BeO分子基态(X^1∑^+)的势能函数研究

Study on the Potential Energy Function for the Ground State X^1Σ^+ of BeO

利用QCISD(T)方法,使用D95(d),cc-PVTZ,6-311++g和6-311++g(3df,2pd)基组,对BeO分子的基态X1∑+平衡结构和谐振频率进行了优化计算。通过对4个基组计算结果进行比较,得出6-311++g(3df,2pd)为最优基组。使用6-311++g(3df,2pd)基组和QCISD(T)方法对基态X1∑+进行单点能扫描计算。采用正规方程组拟合Murrell-Sorbie函数,得出BeO分子的基态分析势能函数,并且计算出BeO分子的光谱常数ωe、ωeχe、Be和αe的值,计算结果与实验值符合得较好。

The equilibrium geometries of the ground electronic states X1Σ+ of BeO molecule were calculated by using the QCISD ( T) method with the basis sets of cc-PVTZ, 6-311 ++ g, D95 (d) and 6-311 ++ g (3df,2pd).Comparing the above mentioned four basis sets,the conclusion is obtained that the basis set 62311 ++ G (3df,2pd) is the most suitable for the energy calculation of BeO molecule.The whole potential curves for the ground electronic state are further scanned by using QCISD (T)/6-311 ++ g (3df,2pd) method.The potential energy functions and relevant spectral constants ωe,ωeχe, Be and αe of this state are obtained by fitting to the Murrell-Sorbie function.The results showed that the spectral constants derived from the Murrell-Sorbie function are in good agreement with the experimental data,which shows that the Murrell-Sorbie function can correctly describe the potential energy function of the ground state of BeO molecule.