An LVC parameterization of the full-dimensional (there are 213 normal modes) diabatic Hamiltonian was performed using the method described in Section 2.2. The resulting LVC Hamiltonian contains a set of 5112 κ and 28968 λ values (not taking into account the degeneracy of the triplet states). A large number of these values is rather small. In order to reduce the number of operator terms in the MCTDH setup, we have defined a threshold of 1 meV for inclusion into the ML-MCTDH simulation. The same holds for the SOC, which in total contains 840 terms. Using the threshold the number of terms reduces to 2768, 11089, and 408 for κ, λ, and the SOC matrix elements, respectively.