Vibrationally excited states in carotenoids: picosecond time-resolved anti-Stokes resonance Raman spectroscopy

✍ Scribed by H. Hayashi; M. Tasumi; G.H. Atkinson

• Publisher: Elsevier Science
• Year: 1991
• Tongue: English
• Weight: 455 KB
• Volume: 178
• Category: Article
• ISSN: 0009-2614
• DOI: 10.1016/0009-2614(91)90270-j

✦ Synopsis

Transient vibrationally excited, ground-state populations of carotenoids have been observed for in viva pigment-protein complexes of Chromatimn vinosum and in vitro samples of the isolated carotenoid spirilloxanthin in benzene solution using picosecond time-resolved anti-Stokes resonance Raman scattering. These populations are formed under the same excitation conditions recently used to detect the transient populations of the ground 'A, and excited 2 'A,and'B, electronic states in the same molecular systems, The time-dependent anti-Stokes resonance Raman band intensities show that these populations decay via vibrational relaxation within 50 ps. These data experimentally confirm an excited state relaxation mechanism postulated to describe the population dynamics among the 'A, 'B,, 2 'A,, and 'B. electronic states in both in viva and in vitro carotenoids.