conical intersection and non-adiabatic dynamics on potential energy surfaces of h2s+ ion

In this work, we tried to find a suitable computational method for determining equilibrium structures and harmonic vibrational frequencies of the two lowest electronic states of h2s+. to understand non-adiabatic dynamics at conical intersections, we calculated the potential energy surfaces of excited electronic states,2a1 and 2b2 by using mrciq method withcasscf wave functions as reference functions with full valence complete active space comprising 17 electrons that are free to active orbitals with aug-cc-pvqz basis set. in this paper, we consider linear vibronic coupling model and evaluate vibronic coupling constant, diabatic frequencies for three modes of h2s+.