PS(X~2Π_r)基态势能函数与光谱常数研究

根据群论及原子分子反应静力学的有关原理,推导了PS基态分子电子态及其合理的离解极限.采用Gaussian 03软件中的密度泛函理论B3LYP和B3P86结合6-311++G(3df,3pd)、6-311++G、6-311G(3df,3pd)、cc-p VTZ和D95基组,对PS分子基态平衡结构和谐振频率进行了计算.通过比较计算结果,发现B3P86方法结合cc-p VTZ基组计算所得结果与实验值最接近.在该水平下对PS分子的基态进行了单点势能扫描计算,利用正规方程组拟合三参数的Murrell-Sorbie函数和修正的Murrell-Sorbie+C6函数,得到了基态PS分子完整的势能函数与相应的光谱常数ωe、ωexe、Be和αe的值.计算结果表明,利用三参数的Murrell-Sorbie函数计算所得的光谱常数与实验数据吻合得更好.

Study on the Analytic potential energy function and spectroscopic constants of the PS molecule

The ground electronic state and the reasonable dissociation limit of PS molecular ion have been correctly determined based on group theory and atomic and molecular reaction statics. The energy, equilibrium geometry and harmonic frequency of the ground electronic state of PS molecular ion have been calculated using the B3LPY and B3P86 method with 6-311++G (3df,3pd),6-311++G,6-311G(3df, 3pd),cc-pVTZ and D95 basis sets. The whole potential curves for the ground electronic state are further scanned using the above method, the potential energy functions and relevant spectroscopic constants of this state are then first obtained by least square fitting to the Murrell-Sorbie function (n=3) and the modified Murrell-Sorbie+c6 function, respectively. The present results show that the calculated results based on the Murrell-Sorbie function (n=3) are in better agreement with the experimental values. Calculation results in the present work may provide theoretical supports for the further study of PS molecular ion.