High pressure fluorescence studies of radiative and nonradiative processes in diphenyl hexatriene, diphenyl octatetraene, and retinyl acetate

The effect of high pressure on the radiative and nonradiative rate parameters of three all-trans polyenes: 1,6-diphenyl-1,3,5-hexatriene (DPH); 1,8-diphenyl-1,3,5,7-octatetraene (DPO); and retinyl acetate (Rac) has been investigated to 10 kbar in methylcyclohexane (MCH) and toluene and to 40 kbar in polymethylmethacrylate (PMMA) and polystyrene (PS). The dependence of the radiative rate on the energy gap between the two lowest excited singlet states is compared to that predicted by a simple first order intensity borrowing expression. Comparison shows good agreement for DPH and DPO. The expression appears to fail for Rac.