Charge transfer excited state energies by perturbative delta self consistent field method

We use our recently outlined perturbative approach to compute the lowest charge transfer excitation energies for a set of tetracynoehylene (TCNE)-hydrocarbon complexes, C2H4-C2F4, NH3-F2, pentacene-C60, and tetraphenyl porphyrin-C60 complexes. Results show that the method can provide a reliable description of charge transfer excitation energies, which are comparable to that obtained by time-dependent density functional theory using specially optimized range-corrected functionals. As the calculation cost of excited state is comparable to the ground state and the calculation of each excited state is independent of others, the method can be easily used to describe the charge transfer excited states of large donor-acceptor complexes containing 200 or more atoms.