Femtosecond time-resolved difference absorption spectroscopy of all-trans-β-Apo-8′-carotenal
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The femtosecond time-resolved difference absorption spectra of all-trans-β-Apo-8′-carotenal have been recorded and analyzed by the singular-value decomposition (SVD) method followed by global fitting using a sequential model for the excited-state energy relaxation. With this model, we have obtained the excited-state absorption spectra and the lifetimes of the corresponding excited states both in nonpolar solvent n-hexane and polar solvent methanol. Three excited states, namely S3(170fs), S2(2.32ps) and S1(26ps) in n-hexane, and two excited states S2(190fs) and S1(9.4ps) in methanol have been observed. The excited-state absorption spectra of all-trans-β-Apo-8′-carotenal in methanol display a red shift and broadeness, while the lifetime of S1 state becomes shorter. It is proposed that these effects are related to the presence of a carbonyl functional group that leads to the solvent effect on the excited-state energy level. At the same time, it is shown that the SVD method is a useful tool in resolving the time-resolved absorption spectra.
Keywordssingular value decomposition femtosecond time-resolved spectroscopy all-trans-β-Apo-8′-carotenal
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- 8.Clayton, R. K., Photosynthesis Physical Mechanisms and Chemical Patterns, London: Cambridge University Press, 1980, 147.Google Scholar
- 9.Sashima, T., Koyama, Y., Yamada, T. et al., The 1Bu+, 1Bu−, 2Ag− energies of crystalline lycopene, β-carotene, and mini-9-β-carotene as determined by resonance-Raman excitation profiles: dependence of the 1Bu− state energy on the conjugation length, J. Phys. Chem. B, 2000, 104: 5011–5019.CrossRefGoogle Scholar
- 12.Becker, R. S., Bensasson, R. V., Lafferty, J. et al., Triplet excited states of carbonyl-containing polyenes, J. Chem. Soc., Faraday Trans., 1978, 274: 2246–2255.Google Scholar