LOCALIZATION IN EXCITED-STATES OF MOLECULES - APPLICATION TO [RU(BPY)3]2+

The properties of electron or exciton localization have been analyzed in solid state physics. Similar concepts can be applied to molecular systems, like [Ru(bpy)3]2+. It is shown that an energy stabilization of the lower excited states through delocalization (order of 10(3) cm-1, mainly through the Ru4d-bpy-pi* mixing) has to be exceeded by a stabilization energy, which results from a nuclear rearrangement DELTA-Q, in order to lead to a localization. DELTA-Q must be very pronounced. Highly resolved emission spectra demonstrate that this is not the case. A series of different experimental results, all based on low-temperature, highly resolved spectra, show that an electron localization does not occur in the lower excited states of [Ru(bpy)3]2+ in the investigated matrices.