Department of Chemistry, Institute for Biophysical Dynamics and James Franck Institute, University of Chicago, IL 60637, USA.
Science. 2013 Jun 21;340(6139):1431-4. doi: 10.1126/science.1233828. Epub 2013 Apr 18.
The design principles that support persistent electronic coherence in biological light-harvesting systems are obscured by the complexity of such systems. Some electronic coherences in these systems survive for hundreds of femtoseconds at physiological temperatures, suggesting that coherent dynamics may play a role in photosynthetic energy transfer. Coherent effects may increase energy transfer efficiency relative to strictly incoherent transfer mechanisms. Simple, tractable, manipulable model systems are required in order to probe the fundamental physics underlying these persistent electronic coherences, but to date, these quantum effects have not been observed in small molecules. We have engineered a series of rigid synthetic heterodimers that can serve as such a model system and observed quantum beating signals in their two-dimensional electronic spectra consistent with the presence of persistent electronic coherences.
支持生物光捕获系统中持续电子相干性的设计原则被这些系统的复杂性所掩盖。这些系统中的一些电子相干性在生理温度下可以持续数百飞秒，这表明相干动力学可能在光合作用能量转移中发挥作用。相干效应相对于严格的非相干转移机制可能会提高能量转移效率。为了探究这些持续电子相干性的基础物理，需要简单、易于处理和可操作的模型系统，但迄今为止，这些量子效应尚未在小分子中观察到。我们设计了一系列刚性的合成杂二聚体，可以作为这样的模型系统，并在它们的二维电子光谱中观察到量子拍频信号，这与持续电子相干性的存在一致。
