Two-Dimensional Electronic-Vibrational Spectroscopy of Coupled Molecular Complexes: A Near-Analytical Approach
Two-Dimensional Electronic-Vibrational Spectroscopy of Coupled Molecular Complexes: A Near-Analytical Approach
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DOI：
10.1021/acs.jpclett.9b00588
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发表时间：
2019-05-02
影响因子：
5.7
通讯作者：
Fleming, Graham R.
中科院分区：
文献类型：
--
作者：
Bhattacharyya, Pallavi;Fleming, Graham R.
本文用近解析方法对振动耦合分子二聚体的二维电子振动(2DEV)谱进行了理论计算。在强耦合二聚体中，IR模与激子之间的电子能隙共振，允许多次红外跃迁，而在具有非共振IR模的弱耦合系统中是被禁止的。这种形式使得相干和布居贡献可以分开研究，并允许有效地计算振动态之间的驰豫速率。在短时间内，我们发现振动相干态对2DEV谱有很大的贡献。它们腐烂得相当快，产生了强烈的种群信号。尽管2DEV谱的解释比弱耦合系统的要复杂得多，但光谱的丰富性和同时考虑可见光和红外跃迁的必要性表明，这种分析对于表征振动效应在超快分子动力学中的作用将是非常有价值的。
This work presents theoretical calculations of the two-dimensional electronic-vibrational (2DEV) spectrum of a vibronically coupled molecular dimer using a near-analytical method. In strongly coupled dimers, where the IR mode is resonant with the electronic energy gap between the excitons, multiple infrared transitions become allowed that are forbidden in weakly coupled systems that have a nonresonant IR mode. This formalism enables the coherences and population contributions to be explored separately and allows efficient calculation of relaxation rates between the vibronic states. At short times, we find strong contributions of vibronic coherences to the 2DEV spectra. They decay fairly rapidly, giving rise to strong population signals. Although the interpretation of 2DEV spectra is considerably more complex than that for weakly coupled systems, the richness of the spectra and the necessity to consider both visible and infrared transition moments suggest that such analysis will be very valuable in characterizing the role of vibronic effects in ultrafast molecular dynamics.