ures S29-S30. Since the various methods cannot be plotted on a common zero, as was the case when only the geometry was changed, the energy of the T 0 state at its minimum energy structure is set at the zero for all curves. The differences in the state taken as the zero reference are less apparent in the plot. Since the T 0 state is dominated by a single configuration, it is expected to be well described by DFT and taken as the zero in Figure . The same data plotted with the S 0 state is in Figure where differences among the methods in the T 0 state are easier to see.