Abstract
Excited-state dynamics of all-trans-spheroidene was studied by time-resolved fluorescence up-conversion method. In order to completely remove fluorescent impurities, spheroidene was purified by two series of alternate alumina and silica-gel chromatography. We used TOPAS, whose repetition rate is 1KHz, as our laser source. The laser output was separated to two beams, one worked as gating pulse, the other was frequency doubled by BBO crystal and was used as pumping pulse. The fluorescence and the gating pulse mixed inside the BBO crystal to generate up-conversion signal. Single photon counting system was used to acquire data. The fluorescence kinetics at different wavelengths was different from each other. The lifetimes of different wavelengths were in between 0.18ps to 0.33ps. After doing dispersion correction and intensity calibration, time-resolved fluorescence up-conversion spectra of all-trans-spheroidene was reconstructed. Single value decomposition followed by global fitting will be used to analyse the spectra.
