Internal Conversion and Vibronic Relaxation from Higher Excited Electronic State of Porphyrins: Femtosecond Fluorescence Dynamics Studies
Internal Conversion and Vibronic Relaxation from Higher Excited Electronic State of Porphyrins: Femtosecond Fluorescence Dynamics Studies
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DOI：
10.1021/jp9941256
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发表时间：
2000-04
影响因子：
3.3
通讯作者：
N. Mataga;and Yutaka Shibata;H. Chosrowjan;N. And;A. Osuka
中科院分区：
文献类型：
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作者：
N. Mataga;and Yutaka Shibata;H. Chosrowjan;N. And;A. Osuka
为了阐明卟啉衍生物高激发电子态的无辐射跃迁以及分子内超快电子振动弛豫的动力学和机制，我们利用荧光上转换技术研究了锌-四苯基卟啉（ZnTPP）和锌-二苯基卟啉衍生物（ZnDPP）在fs−ps时间范围内的荧光动力学.详细的测量ZnTPP在乙醇中已经证明了荧光动力学在整个光谱范围从430至620 nm时，激发到S2状态。时间常数S2荧光在430 nm附近的单指数衰减（约2.3 ps）与S1荧光在600 nm附近的单指数上升一致（固定光谱中0 - 0跃迁的波长），表明在S2 → S1内转换之后立即由超快电子振动再分布引起的弛豫主要在S1底部附近给出较低的电子振动态状态然而，我们已经观察到的动力学弱热f…
To elucidate the dynamics and mechanisms of radiationless transitions from higher excited electronic states as well as the ultrafast intramolecular vibronic relaxation in porphyrin derivatives, we have studied the fluorescence dynamics of Zn-tetraphenylporphyrin (ZnTPP) and Zn-diphenylporphyrin derivatives (ZnDPP) in fs−ps time regimes by means of fluorescence up-conversion technique. Detailed measurements on ZnTPP in ethanol have demonstrated fluorescence dynamics over the whole spectral range from 430 to 620 nm when excited to the S2 state. The time constant (∼2.3 ps) of the single-exponential decay of S2 fluorescence around 430 nm agreed with that of the single-exponential rise of S1 fluorescence around 600 nm (wavelength of 0−0 transition in the stationary spectrum), indicating that the relaxation by the ultrafast vibronic redistribution immediately after S2 → S1 internal conversion mainly gives lower vibronic states near the bottom of the S1 state. However, we have observed the dynamics of weak hot f...