We use the ab initio polariton approach, called parametrized-QED (pQED) to perform the cal-culations. The pQED approach uses Pauli-Fierz Hamiltonian in the Born-Oppenheimer approximation (see Eq. 1) to describe light and matter interactions and use adiabatic electronic states as the basis for the electronic degrees of freedom, and Fock states as the basis for the photonic DOF.