PS(X^2Π_r)基态势能函数与光谱常数研究

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

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.

The ground electronic state and the reasonable dissociation limit of PS molecular ion have been cor-rectly determined based on group theory and atomic and molecular reaction statics .The energy , equilibrium ge-ometry 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 , re-spectively .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 .