Triplett-Lebensdauern von Diphenylpolyenen und deuterierten Stilbenen in eingefrorener Lösung bei 77°K / Triplet Lifetime of Diphenylpolyenes and deuterated Stilbenes in frozen solution at 77°K

Abstract

The lowest triplet states of diphenylpolyenes and of deuterated stilbenes were observed by means of photoflash asportion spectroscopy. The diphenylpolyenes do not show phosphorescence. The triplet lifetime is strongly dependent on triplet energy. This is consistent with the known influence of Franck-Condon factors. The triplet lifetime of partially deuterated stilbenes depends on the number and the position of the deuterium atoms. The effect of olefinic monodeuteration on the non-radiative process is approximately 16 times larger than that of deuteration at an aromatic position. The observations can be explained in terms of isotope effects on vibronic spin-orbit coupling.