To explain the qualitative change in the computed states, we examined their leading ECSFs in the ECIS and ECISD calculations and compared them to the direct full-system CIS and CISD calculations. The results are given in Table . As can be seen, ECIS predicts the S 1 -S 4 states to be local S 1 excitations on the four guanines, while the S 5 -S 8 states are S 2 local excitations. Note that the geometry is not symmetric, and therefore there is a single leading ECSF in each state, unlike in the symmetric Franck-Condon geometry. Also note that the direct full-system CIS calculation predicts nearly the same order of states, except that S 8 and S 9 are swapped.