FLUORESCENCE FROM THE S(1)(2(1)AG) STATE OF ALL-TRANS-BETA-CAROTENE

S1 --> S0 fluorescence spectra of all-trans-beta-carotene in n-hexane, toluene, and carbon disulfide at room temperature were recorded. The shape and maxima of these spectra at 830 +/- 10 nm were the same in all three solvents. The energy of the S1 (2 1A(g)) state was found at 13200 +/- 300 cm-1. The fluorescence quantum yields of all-trans-beta-carotene for the above-mentioned solvents are equal to (0.5 +/- 0.2) x 10(-5), (0.8 +/- 0.2) x 10(-5) and (2.0 +/- 0.3) x 10(-5), respectively. The results are discussed in terms of energy transfer from the all-trans-beta-carotene S1 state to chlorophylls in vivo.