Segarra-Martí Javier, Mukamel Shaul, Garavelli Marco, Nenov Artur, Rivalta Ivan
Université de Lyon, École Normale Supérieure de Lyon, CNRS, Université Claude Bernard Lyon 1, Laboratoire de Chimie UMR 5182, 69342, Lyon, France.
Department of Chemistry, University of California, Irvine, CA, 92697-2025, USA.
Top Curr Chem (Cham). 2018 Jun 1;376(3):24. doi: 10.1007/s41061-018-0201-8.
We introduce the basic concepts of two-dimensional electronic spectroscopy (2DES) and a general theoretical framework adopted to calculate, from first principles, the nonlinear response of multi-chromophoric systems in realistic environments. Specifically, we focus on UV-active chromophores representing the building blocks of biological systems, from proteins to nucleic acids, describing our progress in developing computational tools and protocols for accurate simulation of their 2DUV spectra. The roadmap for accurate 2DUV spectroscopy simulations is illustrated starting with benchmarking of the excited-state manifold of the chromophoric units in a vacuum, which can be used for building exciton Hamiltonians for large-scale applications or as a reference for first-principles simulations with reduced computational cost, enabling treatment of minimal (still realistic) multi-chromophoric model systems. By adopting a static approximation that neglects dynamic processes such as spectral diffusion and population transfer, we show how 2DUV is able to characterize the ground-state conformational space of dinucleosides and small peptides comprising dimeric chromophoric units (in their native environment) by tracking inter-chromophoric electronic couplings. Recovering the excited-state coherent vibrational dynamics and population transfers, we observe a remarkable agreement between the predicted 2DUV spectra of the pyrene molecule and the experimental results. These results further led to theoretical studies of the excited-state dynamics in a solvated dinucleoside system, showing that spectroscopic fingerprints of long-lived excited-state minima along the complex photoinduced decay pathways of DNA/RNA model systems can be simulated at a reasonable computational cost. Our results exemplify the impact of accurate simulation of 2DES spectra in revealing complex physicochemical properties of fundamental biological systems and should trigger further theoretical developments as well as new experiments.
我们介绍了二维电子光谱（2DES）的基本概念以及用于从第一原理计算实际环境中多发色团系统非线性响应的通用理论框架。具体而言，我们关注代表生物系统构建模块（从蛋白质到核酸）的紫外活性发色团，描述了我们在开发用于精确模拟其二维紫外光谱的计算工具和协议方面取得的进展。准确的二维紫外光谱模拟路线图从真空中发色团单元激发态流形的基准测试开始说明，其可用于构建用于大规模应用的激子哈密顿量，或作为计算成本降低的第一原理模拟的参考，从而能够处理最小（但仍现实）的多发色团模型系统。通过采用忽略光谱扩散和布居转移等动态过程的静态近似，我们展示了二维紫外光谱如何通过跟踪发色团间电子耦合来表征包含二聚发色团单元（在其天然环境中）的二核苷和小肽的基态构象空间。恢复激发态相干振动动力学和布居转移后，我们观察到芘分子预测的二维紫外光谱与实验结果之间有显著的一致性。这些结果进一步导致了对溶剂化二核苷系统中激发态动力学的理论研究，表明沿着DNA/RNA模型系统复杂的光诱导衰变路径，长寿命激发态极小值的光谱指纹可以以合理的计算成本进行模拟。我们的结果例证了二维电子光谱光谱精确模拟在揭示基本生物系统复杂物理化学性质方面的影响，应会引发进一步的理论发展以及新的实验。
