近日，德国奥西茨基大学Christoph Lienau团队研究了四极性染料光激发动力学中振动耦合驱动的对称破缺和溶剂化。该项研究成果发表在2025年8月20日出版的《自然-化学》杂志上。

四极性染料，如受体-给体-受体分子，在非线性光学和光伏领域有着重要的应用。它们也是探索光致电荷转移动力学的通用模型。这些分子中电子和振动耦合之间的相互作用可能打破激发态对称，导致分子内电荷分离和明显的溶剂变色。在实验上，区分分子内振动耦合和溶剂重组在初始电荷转移动力学中的作用一直是一个挑战。

研究组以超快泵浦探针和二维电子能谱为主题，研究了一种典型的四极性染料在极性和非极性溶剂中的应用。他们的结果表明，振子耦合在光诱导电荷转移的前~50fs期间引发激发态对称性破缺，而溶剂诱导电荷局域化在稍后时间开始。量子动力学和电子结构模拟支持他们的实验发现。该结果揭示了光激发分子中溶剂化动力学的细节，并提出了通过振动耦合来操纵它们的策略。

附：英文原文

Title: Vibronic coupling-driven symmetry breaking and solvation in the photoexcited dynamics of quadrupolar dyes

Author: Winte, Katrin, Souri, Somayeh, Lnemann, Daniel C., Zheng, Fulu, Madjet, Mohamed El-Amine, Frauenheim, Thomas, Kraus, Teresa, Mena-Osteritz, Elena, Buerle, Peter, Tretiak, Sergei, De Sio, Antonietta, Lienau, Christoph

Issue&Volume: 2025-08-20

Abstract: Quadrupolar dyes, such as acceptor–donor–acceptor molecules, are highly relevant for applications in nonlinear optics and photovoltaics. They are also versatile models for exploring photoinduced charge-transfer dynamics. The interplay between electronic and vibronic couplings in these molecules may break excited-state symmetry, resulting in intramolecular charge separation and pronounced solvatochromism. Experimentally, distinguishing the roles of intramolecular vibronic coupling and solvent reorganization for the initial charge-transfer dynamics has been challenging so far. Here we investigate a prototypical quadrupolar dye in polar and non-polar solvents using ultrafast pump–probe and two-dimensional electronic spectroscopy. Our results reveal that vibronic couplings initiate excited-state symmetry breaking during the first ~50fs of the photoinduced charge transfer, whereas solvent-induced charge localization sets in at later times. Quantum dynamics and electronic structure simulations support our experimental findings. Our results reveal the details of solvation dynamics in photoexcited molecules and suggest strategies for their manipulation through vibronic couplings.

DOI: 10.1038/s41557-025-01908-7

Source: https://www.nature.com/articles/s41557-025-01908-7