To find the optimal range-separation parameters, we computed J * on a grid of (α, ω) pairs using the LC-BLYP functional and 6-31G(d) basis set at the B3LYP /def2TZVP optimized S 0 ground-state geometry. Additional computational details for this section are reported in Section Often 2D tuning optimization plots have a distinct valley where the minimal points for a given α-value are located . For [Fe(cpmp) 2 ] 2+ in the S 0 state, the resulting two-dimensional plot of J * (α, ω) is presented by the colored surface in Fig. and displays a global minimum of J * at (0.00; 0.14) located in the valley marked with white circles (for exemplary 1D-cuts at α=0 see Fig.