Assessment of the ΔSCF-DFT approach for electronic excitations in organic dyes

This paper assesses the accuracy of the ΔSCF method for computing low-lying HOMO→LUMO transitions in organic dye molecules. For a test set of vertical excitation energies of 16 chromophores, surprisingly similar accuracy is observed for time-dependent density functional theory and for ΔSCF density functional theory. In light of this performance, we reconsider the ad hoc ΔSCF prescription and demonstrate that it formally obtains the exact stationary density within the adiabatic approximation, partially justifying its use. The relative merits and future prospects of ΔSCF for simulating individual excited states are discussed.United States. Dept. of Energy (Office of Sciences, and Office of Basic Energy Sciences under Award Number DE-SC0001088)Chesonis Family Foundation (Solar Revolution Project Fellowship)David & Lucile Packard Foundation (Fellowship)United States. Dept. of Energy (Energy Frontiers Research Center)United States. Dept. of Energy (Center of Excitonics