Note:
For intramolecular charge transfer in the excited state, several models are discussed in the literature based on the molecular structure of the final state reached upon photo-induced ICT: planar intramolecular charge transfer (PICT) or twisted intramolecular charge transfer (TICT). For example, an ICT has been proposed to be responsible for the strongly Stokes-shifted additional fluorescence band in fluorescent molecules with two fluorescence bands (dual fluorescent molecules).