Carotenoid fluorescence

✍ Scribed by Tomas Gillbro; Richard J. Cogdell

• Publisher: Elsevier Science
• Year: 1989
• Tongue: English
• Weight: 459 KB
• Volume: 158
• Category: Article
• ISSN: 0009-2614
• DOI: 10.1016/0009-2614(89)87342-7

✦ Synopsis

Fluorescence excitation and emission spectra arc reported from the carotenoids P-carotene, rhodopin and spheroidenone in carbon disulfide. From the small Stokes shift and the high emission anisotropy it is concluded that the fluorescence is emitted durmg the 16,-r lA, transition. From the small quantum yields, of about 3 X IO-' for spheroidenone and 6 X IO-' for p-carotene, and the 15 ps ground-state recovery lifetime for spheroidenone combined with a natural radiative lifetime of I-10 ns, it is concluded that a fast (30-300 fs) non-radiative relaxation occurs. This probably represents the transition from the IB, to a low-lying 2A, state. Anomalities in the excitation spectra also indicate that this process competes efficiently with vibrational relaxation within the lB, state.