Ultrafast photo-induced charge transfer unveiled by two-dimensional electronic spectroscopy
Ultrafast photo-induced charge transfer unveiled by two-dimensional electronic spectroscopy
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DOI：
10.1063/1.4720492
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发表时间：
2012-05-28
影响因子：
4.4
通讯作者：
Christensson, Niklas
中科院分区：
文献类型：
--
作者：
Bixner, Oliver;Lukes, Vladimir;Christensson, Niklas
激子态与电荷转移态的相互作用在化学、生物学和物理学中的光诱导电荷转移过程中起着核心作用。在这项工作中，我们使用二维电子光谱（2D-ES），泵浦探测测量和量子化学的组合，以研究超快CT动力学在不同的氧化态的镥双酞菁二聚体。结果发现，在阴离子形式中，强CT-激子相互作用和电子不对称性诱导的抗衡离子的组合，使CT之间的两个大环的复杂的30 fs的时间尺度上。光激发后，链的电子和空穴转移步骤引起的特征交叉峰动态的电子二维光谱中，我们监测如何激发态电荷密度最终本地化的大环最接近的反离子在100 fs内。在自由基物种的动力学的比较进一步阐明CT状态如何调制的电子结构和调谐FS-反应动力学。我们的实验证明了2D-ES与其他方法相结合的独特能力，以破译超快CT动力学。(C)2012年美国物理学会。[http：//dx.doi.org/10.1063/1.4720492]
The interaction of exciton and charge transfer (CT) states plays a central role in photo-induced CT processes in chemistry, biology, and physics. In this work, we use a combination of two-dimensional electronic spectroscopy (2D-ES), pump-probe measurements, and quantum chemistry to investigate the ultrafast CT dynamics in a lutetium bisphthalocyanine dimer in different oxidation states. It is found that in the anionic form, the combination of strong CT-exciton interaction and electronic asymmetry induced by a counter-ion enables CT between the two macrocycles of the complex on a 30 fs timescale. Following optical excitation, a chain of electron and hole transfer steps gives rise to characteristic cross-peak dynamics in the electronic 2D spectra, and we monitor how the excited state charge density ultimately localizes on the macrocycle closest to the counter-ion within 100 fs. A comparison with the dynamics in the radical species further elucidates how CT states modulate the electronic structure and tune fs-reaction dynamics. Our experiments demonstrate the unique capability of 2D-ES in combination with other methods to decipher ultrafast CT dynamics. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4720492]