Solvent effects on excitation relaxation dynamics of a keto-carotenoid, siphonaxanthin.
Solvent effects on relaxation dynamics of a keto-carotenoid, siphonaxanthin, were investigated by means of the femtosecond time-resolved fluorescence spectroscopy. After excitation to the S2 state of siphonaxanthin, the S2-->1(n, pi*) internal conversion occurred with a time constant of 30-35 fs, followed by the 1(n, pi*)-->S1 internal conversion in 180-200 fs. Solvent dependence of the internal conversions was small, however intensities of the S1 fluorescence with its lifetime of longer than 10 ps were enhanced in methanol. These were explained by displacement of the potential surfaces and interaction through the hydrogen-bond between the C=O group of siphonaxanthin and solvents.
Akimoto
Seiji
S
Molecular Photoscience Research Center, Kobe University, 657-8501, Kobe, Japan. akimoto@hawk.kobe-u.ac.jp
Yokono
Makio
M
Higuchi
Michiya
M
Tomo
Tatsuya
T
Takaichi
Shinichi
S
Murakami
Akio
A
Mimuro
Mamoru
M
D006860:Hydrogen Bonding; D007700:Kinetics; D000432:Methanol / Q000737:chemistry*; D008968:Molecular Conformation; D012997:Solvents / Q000737:chemistry; D013050:Spectrometry, Fluorescence; D013997:Time Factors; D024341:Xanthophylls / Q000737:chemistry*
D012997:Solvents; D024341:Xanthophylls; C003314:siphonaxanthin; D000432:Methanol