Sub-mu-second time-resolved absorption spectroscopy of a polar carotenoid analogue, 2-(all-trans-retinylidene)indan-1,3-dione; formation of the dication by direct triplet-excited sensitization

Sub-mu-second time-resolved difference absorption spectra of a polar carotenoid analogue, 2-(all-trans-retinylidene)indan-1,3-dione (RetInd), were recorded in tetrahydrofuran at room temperature upon anthracene-sensitized triplet excitation. The 'cation' of RetInd showed vibrational structure in its absorption spectrum, and its lifetime was determined to be 15(mu)s.