Femtosecond pump-supercontinuum probe and transient lens spectroscopy of adonixanthin
Femtosecond pump-supercontinuum probe and transient lens spectroscopy of adonixanthin
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DOI：
10.1016/j.abb.2008.11.026
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发表时间：
2009-03-15
影响因子：
3.9
通讯作者：
Oum, Kawon
中科院分区：
文献类型：
--
作者：
Lenzer, Thomas;Schubert, Steffen;Oum, Kawon
利用泵浦-超连续谱探测（PSCP）和瞬态透镜（TL）光谱研究了侧金盏花黄素在有机溶剂中光激发到S（2）态后的超快内转换动力学。在344-768 nm范围内的瞬态PSCP光谱提供了S（0）-> S（2）基态漂白和S（1）-> S（0）激发态吸收的光谱演化。在丙酮和甲醇中，S（2）-> S（1）IC的时间常数分别为tau（2）= 115和111 fs，S（1）-> S（0）IC的时间常数分别为tau（1）= 6.4和5.8 ps。tau（1）的极性依赖性很小，这表明在β-紫罗兰酮环上具有羰基取代的C（40）类胡萝卜素的最低激发态中，分子内电荷转移（ICT）的重要性可以忽略不计。发现了S（1）-> S（0）ESA带的蓝移和光谱变窄（可能是由于溶剂化动力学），以及在高泵浦能量下通过共振双光子电离形成侧金盏花黄素径向阳离子。All rights reserved.
The ultrafast internal conversion (IC) dynamics of adonixanthin in Organic solvents were studied by pump-supercontinuum probe (PSCP) and transient lens (TL) spectroscopy after photoexcitation to the S(2) state. Transient PSCP spectra in the range 344-768 nm provided the spectral evolution of the S(0) -> S(2) ground state bleach and S(1) -> S(0) excited state absorption. Time constants were tau(2) = 115 and 111 fs for the S(2) -> S(1) IC and tau(1) = 6.4 and 5.8 ps for the S(1) -> S(0) IC in acetone and methanol, respectively. There was only an insignificant polarity dependence of tau(1), underlining the negligible importance of intramolecular charge transfer (ICT) in the lowest-lying excited state of C(40) carotenoids with carbonyl substitution on the beta-ionone ring. A blueshift and a spectral narrowing of the S(1) -> S(0) ESA band, likely due to solvation dynamics, and formation of the adonixanthin radial cation at high Pump energies via resonant two-photon ionization were found. (C) 2008 Elsevier Inc. All rights reserved.