Šímová Ivana, Chrupková Petra, Gardiner Alastair T, Koblížek Michal, Kloz Miroslav, Polívka Tomáš
Department of Physics, Faculty of Science, University of South Bohemia, Branišovská 1760, 370 05 České Budějovice, Czech Republic.
The Extreme Light Infrastructure ERIC, ELI Beamlines Facility, Za Radnicí 835, Dolní Břežany 252 41, Czech Republic.
J Phys Chem Lett. 2024 Jul 25;15(29):7466-7472. doi: 10.1021/acs.jpclett.4c01272. Epub 2024 Jul 15.
Femtosecond stimulated Raman spectroscopy (FSRS) and transient absorption data measured in a single experiment are used to determine the vibronic properties of the S state of linear carotenoids with different conjugation lengths. The Raman band corresponding to the C═C stretching mode in the S state peaks at 1799 cm (neurosporene), 1802 cm (spheroidene), and 1791 cm (lycopene). Contrary to the ground state C═C mode, variation of the C═C stretching mode in the S state is small and does not follow a linear dependence on . The lifetime of the Raman band matches the S decays obtained from transient absorption, confirming its S state origin. Direct comparison of transient absorption and FSRS signals allowed us to assign Raman signatures of nonrelaxed S and S states. For lycopene, FSRS data identified a component associated with a downshifted ground state C═C mode, which matches the dynamics of the S* signal observed in transient absorption data.
在单个实验中测量的飞秒受激拉曼光谱（FSRS）和瞬态吸收数据用于确定具有不同共轭长度的线性类胡萝卜素S态的振转性质。S态中对应于C═C伸缩模式的拉曼带在1799 cm（八氢番茄红素）、1802 cm（球形烯）和1791 cm（番茄红素）处达到峰值。与基态C═C模式相反，S态中C═C伸缩模式的变化很小，并且不遵循对……的线性依赖关系。拉曼带的寿命与从瞬态吸收获得的S态衰减相匹配，证实了其S态起源。瞬态吸收和FSRS信号的直接比较使我们能够确定未弛豫的S态和S态的拉曼特征。对于番茄红素，FSRS数据确定了一个与基态C═C模式下移相关的成分，这与瞬态吸收数据中观察到的S*信号的动力学相匹配。
