Electronic structure of the SrH⁺ and BaH⁺ molecules with dipole moment and rovibrational calculations

The alkaline-earth metal hydrides and their corresponding ions are heteronuclear molecules that are essential in many fields especially in astrophysics and spectroscopy such as sunspots, stars, nebulae, the interstellar medium and chemical engineering. They are important systems in spectroscopy due to their visible bands which emerge in the absorption spectrum of sun. Due to the importance of hydride species and the lack of theoretical studies on some astronomical diatomic molecules is a main reason to investigate their electronic structure. The adiabatic potential energy curves and the static dipole moment curves of the low-lying electronic states of strontium hydride cation SrH⁺ and barium hydride cation BaH⁺ have been investigated using ab initio CASSCF/(MRCI + Q) calculations. The spectroscopic parameters T_e, R_e, ω_e, B_e, the dipole moment μ_e, and the dissociation energy D_e were calculated for the bound states. Using the canonical function approach, the rovibrational constants E_v, B_v, D_v and the turning points R_min and R_max for the ground and several excited states have been determined.