Femtosecond Stimulated Raman Spectroscopy of Linear Carotenoids.
J Phys Chem Lett
; 15(29): 7466-7472, 2024 Jul 25.
Article
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| ID: mdl-39008850
ABSTRACT
Femtosecond stimulated Raman spectroscopy (FSRS) and transient absorption data measured in a single experiment are used to determine the vibronic properties of the S1 state of linear carotenoids with different conjugation lengths. The Raman band corresponding to the CâC stretching mode in the S1 state peaks at 1799 cm-1 (neurosporene), 1802 cm-1 (spheroidene), and 1791 cm-1 (lycopene). Contrary to the ground state CâC mode, variation of the CâC stretching mode in the S1 state is small and does not follow a linear dependence on N. The lifetime of the Raman band matches the S1 decays obtained from transient absorption, confirming its S1 state origin. Direct comparison of transient absorption and FSRS signals allowed us to assign Raman signatures of nonrelaxed S1 and S0 states. For lycopene, FSRS data identified a component associated with a downshifted ground state CâC mode, which matches the dynamics of the S* signal observed in transient absorption data.
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MEDLINE
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En
Ano de publicação:
2024
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Article