Fluorescence spectroscopy

Good afternoon,

If the compound can rapidly change conformation, new way of desexcitation appears ( through interaction with solvent for example by rotation of bonds (waves on the diagram) and the amount of energy that "can be use " for fluorescence is less important.

Google, for example Twisted intramolecular charge transfer (TICT) states.

The time of fluorescence depends on the conformation of the fluorescent substance and the environment. See, for example, the attached file.