Here E (α) are the vertical ionization energies calculated at the equilibrium geometry of the neutral, κ are the coefficients of expansion of the potential along the fully symmetric coordinates, and λ is the linear diabatic coupling. We computed the parameters of the KDC Hamiltonian using ab initio CC and EOM-CC methods. We considered methods in which the CC expansion was truncated to singles and doubles (CCSD), singles, doubles and triples (CCSDT), as well as singles, doubles, triples, and quadruples (CCSDTQ). We computed the geometry of the neutral ozone and its harmonic frequencies and normal coordinates with CCSDT/ANO1 ; the Cartesian coordinates are given in the SI.