Accurate Assignments of Excited-State Resonance Raman Spectra: A Benchmark Study Combining Experiment and Theory
Accurate Assignments of Excited-State Resonance Raman Spectra: A Benchmark Study Combining Experiment and Theory
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DOI：
10.1021/acs.jpca.7b09467
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发表时间：
2017-10-19
影响因子：
2.9
通讯作者：
Elles, Christopher G.
中科院分区：
文献类型：
--
作者：
Barclay, Matthew S.;Quincy, Timothy J.;Elles, Christopher G.
飞秒受激拉曼散射（FSRS）通过跟踪分子振动光谱的演化来探测处于电子激发态的分子的结构动力学。解释动力学需要准确的分配，以连接振动带与特定的核运动的激发分子。然而，FSRS信号的分配往往是复杂的模式特定的共振增强效应，难以计算的分子在电子激发态。我们提出了一系列的八个芳基取代的噻吩衍生物的基准结果表明，计算的非共振拉曼光谱可以用来分配实验频带的基础上，比较结构相似的化合物和仔细考虑的共振条件。重要的是，我们表明，直接比较与非共振计算可能会导致不正确的分配的实验光谱，如果共振条件被忽略。这些结果突出了共振增强效应在分配FSRS光谱中的重要性。
Femtosecond stimulated Raman scattering (FSRS) probes the structural dynamics of molecules in electronically excited states by following the evolution of the vibrational spectrum. Interpreting the dynamics requires accurate assignments to connect the vibrational bands with specific nuclear motions of an excited molecule. However, the assignment of FSRS signals is often complicated by mode-specific resonance enhancement effects that are difficult to calculate for molecules in electronically excited states. We present benchmark results for a series of eight aryl- substituted thiophene derivatives to show that calculated off resonance Raman spectra can be used to assign experimental bands on the basis of a comparison of structurally similar compounds and careful consideration of the resonance condition. Importantly, we show that direct comparison with the off-resonant calculations can lead to incorrect assignments of the experimental spectrum if the resonance condition is neglected. These results highlight the importance of resonance enhancement effects in assigning FSRS spectra.