Two-dimensional electronic spectroscopy can fully characterize the population transfer in molecular systems
Two-dimensional electronic spectroscopy can fully characterize the population transfer in molecular systems
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DOI：
10.1063/1.4962577
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发表时间：
2016-09-28
影响因子：
4.4
通讯作者：
Brixner, Tobias
中科院分区：
文献类型：
--
作者：
Dostal, Jakub;Benesova, Barbora;Brixner, Tobias
复杂系统中的激发能量转移通常通过一系列中间状态进行。时间分辨光谱的目标之一是识别所获取的实验数据中所有这些的光谱特征，并表征它们之间的能量转移方案。众所周知，在瞬态吸收光谱的情况下，即使采取许多简化考虑，这种分解也是不明确的。与瞬态吸收相反，吸收二维光谱直观地类似于群体转移矩阵。因此，似乎可以明确地分解二维光谱。在这里，我们展示了所有必要的信息都被编码在吸收二维和线性吸收光谱的组合中。我们建立了一个简单的模型，描述了广泛的吸收二维光谱，并通过分析证明它们可以唯一地反转为物理参数，完全确定各个成分的物种相关光谱以及所有连接的内在速率常数。由于该模型的矩阵公式，适合通过拟合实验二维和吸收光谱的组合来有效地进行数值反演所需的快速计算机计算。此外，该模型允许将二维光谱几乎明确地分解为其受激发射、基态漂白和激发态吸收成分。示例性地说明了数值过程。 Published by AIP Publishing.
Excitation energy transfer in complex systems often proceeds through series of intermediate states. One of the goals of time-resolved spectroscopy is to identify the spectral signatures of all of them in the acquired experimental data and to characterize the energy transfer scheme between them. It is well known that in the case of transient absorption spectra such decomposition is ambiguous even if many simplifying considerations are taken. In contrast to transient absorption, absorptive 2D spectra intuitively resemble population transfer matrices. Therefore, it seems possible to decompose the 2D spectra unambiguously. Here we show that all necessary information is encoded in the combination of absorptive 2D and linear absorption spectra. We set up a simple model describing a broad class of absorptive 2D spectra and prove analytically that they can be inverted uniquely towards physical parameters fully determining the species-associated spectra of individual constituents together with all connecting intrinsic rate constants. Due to the matrix formulation of the model, it is suitable for fast computer calculation necessary to efficiently perform the inversion numerically by fitting the combination of experimental 2D and absorption spectra. Moreover, the model allows for decomposition of the 2D spectrum into its stimulated emission, ground-state bleach, and excited-state absorption components almost unambiguously. The numerical procedure is illustrated exemplarily. Published by AIP Publishing.