Theoretical Investigations On Spectroscopoc Properties Of Loy-lying Electronic States Of PO⁺ And S₂⁺ Cation

Molecular potential energy curve give one absolute description of molecular and electronic energy with Born-Oppenheimer approximation, namely molecular energy,geometry,force constants and spectrum peop erties, At the same time, The potential energy function of the diatomic molecule is considered as the basic issues. it is also important to investigate atomic and molecular collision and reaction and is of special importance in the atom-cluster growth, dissociation and stability analyses. We needs a long-term practical The theory study of molecular accurate analytic potential energy function, It is one of the important branches in atomic and molecular physics.In the present work, the PEC and spectroscopic parameters for two diatomic PO+ and S2+ cation are calculated. The effects on the spectroscopic parameters and molecular constants by some corrections are considered. For example, the core valance correlation correction, relativistic correction and energy base extrapolation of this group.First, the PECs of 18 Λ-S states of PO+ cation, 18 Λ-S states of S2+ cation are calculated using the internally contracted multi-reference configuration interaction method(ic MRCI) with Dunning’s correlation consistent basis sets. We get the spectroscopic parameters( De, Te, Re, ωe, ωexe, ωeye, Be and αe) by solving the rovibrational Schr?dinger equation with Numerov’s method.Then, the spin-orbit(SO) coupling effect on the spectroscopic parameters is included using the internally contracted multi-reference configuration interaction method(ic MRCI). The PECs of 50 Ω states of PO+ cation, and 56 Ω states of S2+ cation are calculated.Finally, the transition properties of S2+cation is studied with the help of LEVEL Program. we calculate the Frank-Condon factors, transitions dipole moments and radiative lifetimes at different vibrational levels for the tow transitions, a4Π1/2, u-X2Π1/2, g and A2Π1/2, u-X2Π1/2.On the whole, the Davidson, core-valence correlation, scalar relativistic corrections SO coupling ef fect and energy base extrapolation of this group obviously improve the spectroscopic parameters quality. The transition properties are studied which should be good references for future experimental or theoretical research.