Electronic Properties of Materials, Faculty of Physics, University of Vienna, Strudlhofgasse 4, 1090 Vienna, Austria.
J Phys Chem B. 2011 May 12;115(18):5383-91. doi: 10.1021/jp109442b. Epub 2011 Feb 17.
In this work we analyze how nuclear coherences modulate diagonal and off-diagonal peaks in two-dimensional electronic spectroscopy. 2D electronic spectra of pinacyanol chloride are measured with 8 fs pulses, which allows coherent excitation of the 1300 cm(-1) vibrational mode. The 2D spectrum reveals both diagonal and off-diagonal peaks related to the vibrational mode. On early time scales, up to 30 fs, coherent dynamics give rise to oscillations in the amplitudes, positions, and shapes of the peaks in the 2D spectrum. We find an anticorrelation between the amplitude and the diagonal width of the two diagonal peaks. The measured data are reproduced with a model incorporating a high frequency mode coupled to an electronic two-level-system. Our results show that these anticorrelated oscillations occur for vibrational wavepackets and not exclusively for electronic coherences as has been assumed previously.
在这项工作中，我们分析了核相干如何调制二维电子光谱中的对角和非对角峰。使用 8fs 脉冲测量了 pinacyanol 氯化物的二维电子光谱，这允许对 1300cm(-1)的振动模式进行相干激发。二维光谱显示了与振动模式相关的对角和非对角峰。在早期时间尺度上，直到 30fs，相干动力学导致二维光谱中峰的幅度、位置和形状的振荡。我们发现两个对角峰的幅度和对角宽度之间存在反相关。用一个包含高频模式和一个电子双能级系统的模型重现了测量数据。我们的结果表明，这些相关的振荡发生在振动波包中，而不仅仅是电子相干，如之前假设的那样。
