Department of Physics, School of Physical Science and Technology, Ningbo University, Ningbo 315211, China.
Beijing National Laboratory for Molecular Sciences, State Key Laboratory for Structural Chemistry of Unstable and Stable Species, CAS Research/Education Center for Excellence in Molecular Sciences, Institute of Chemistry, Chinese Academy of Sciences, Zhongguancun, Beijing 100190, China.
J Phys Chem Lett. 2023 Feb 2;14(4):838-845. doi: 10.1021/acs.jpclett.2c03413. Epub 2023 Jan 19.
Two-dimensional electronic spectroscopy (2DES) has been widely employed as an efficient tool to reveal the impact of intermolecular electronic and/or vibronic quantum coherence on excitation energy transfer in light-harvesting complexes. However, intramolecular vibrational coherence would also contribute to oscillating signals in 2D spectra, along with the intermolecular coherence signals that are directly related to energy transfer. In this work, the possibility of screening the vibrational coherence signals is explored through polarization-dependent 2DES. The all-parallel (AP) and double-crossed (DC) polarization-dependent two-dimensional rephasing spectra (2DRS) are simulated for a minimalist heterodimer model with vibrational coupling. By combining the DC-2DRS and the 2D beating maps, we demonstrate that the population and vibrational coherence signals can be largely suppressed, resulting in highlighted intermolecular electronic and vibronic coherence signals. Moreover, the AP- and DC-2DBMs show rather different patterns at the vibrational frequency, indicating a possible way to identify pure vibrational coherence.
二维电子光谱（2DES）已被广泛应用于揭示分子间电子和/或振子量子相干对光捕获复合物中激发能量转移的影响。然而，分子内振动相干也会导致 2D 光谱中出现振荡信号，以及与能量转移直接相关的分子间相干信号。在这项工作中，通过偏振相关 2DES 探索了筛选振动相干信号的可能性。对具有振动耦合的最小异质二聚体模型进行了全平行（AP）和双交叉（DC）偏振相关二维重相位（2DRS）光谱模拟。通过结合 DC-2DRS 和 2D 拍频图，我们证明可以很大程度上抑制种群和振动相干信号，从而突出显示分子间电子和振子相干信号。此外，AP- 和 DC-2DBM 在振动频率上呈现出相当不同的模式，这表明了一种识别纯振动相干的可能方法。
