应用CASSCF方法精确计算OH分子A^2∑^+态势能曲线

Accurate calculations of the A^2∑^+ potential energy curve for OH molecule using the CASSCF method

应用Gaussian03程序包中提供的完全活性空间自洽场(CASSCF)方法,采用多种标准基组对OH分子A^2∑^+态的几何结构进行了优化和势能曲线计算、并将计算结果拟合成了解析的Murrell-Sorbie函数.利用得到的解析势能函数进一步计算了该态的光谱常数,并与实验结果进行了比较.此外,本文还给出了一种新的活性空间的选择方法.

The equilibrium geometric for A2∑ ＋ electronic state of OH molecule is optimized using the Complete Active Space SCF （CASSCF） method with a variety of basis sets. Simultaneously, the poten- tial energy curve for this state is calculated in the same standard. Then, we fit the computational result into the analytical Murrell-Sorbie function. We calculate the spectroscopy constants by means of the analytical potential energy function and compare the computational result with the experimental result. In addition, this paper also gives out a novel way to select the complete active space.