Triplet–triplet and singlet–singlet energy-transfer studies between t-stilbene and 7-aminocoumarin laser dyes
Singlet–singlet and triplet–triplet energy-transfer processes between t-stilbene and 7-aminocoumarin dyes, viz. C 1, C 102, C 1F and C 153, have been studied. Singlet–singlet energy-transfer rate constants and critical transfer distances claculated for t-stilbene and coumarins suggest that they take place via a long-range coulombic mechanism. The triplet–triplet energy-transfer studies carried out by pulse radiolysis suggest that they take place via an exchange mechanism.