In the following, we present MECIs obtained via optimization on surrogate potentials that are determined from DFT/MRCI(2) single point energies, and compare it to the MECIs computed using analytical ab initio MRCI gradients and non-adiabatic couplings. The representative examples discussed below have been previously studied in detail: the accidental S 0 /S 1 ConIns of "twisted-pyramidalized" ethylene, "transoid" butadiene, and "twisted" fulvene,. The Cartesian geometries of all the optimized MECIs from the different sampled surrogates are provided as supplementary material. However, a comparison of key internal coordinates between the mean DFT/MRCI(2) structures, computed from the optimized MECI over the 50 surrogates constructed from different training data, and those obtained using ab initio MRCI is shown in Table . The nuclear configurations for each of the structures discussed below are shown in Fig. , where the atom numbering employed will be used throughout The DFT/MRCI(2) optimized MECI parameters for ethylene, butadiene and fulvene are summarized in Tables and. Table compares the DFT/MRCI(2) MECI topographies to those obtained from ab initio MRCI methods, while Table shows the overlap of the branching spaces for each of the methods. For rows and columns corresponding to DFT/MRCI(2), the presented value is the arithmetic mean ± the standard deviation over the values obtained from the set of 50 surrogates.