通过五阶飞秒二维光谱研究分子二聚体中的激子-激子湮灭。

Mapping of exciton-exciton annihilation in a molecular dimer via fifth-order femtosecond two-dimensional spectroscopy.

机构信息

Institut für Physikalische und Theoretische Chemie, Universität Würzburg, Emil-Fischer-Str. 42, 97074 Würzburg, Germany.

Institut für Physikalische und Theoretische Chemie, Universität Würzburg, Am Hubland, 97074 Würzburg, Germany and Center for Nanosystems Chemistry (CNC), Theodor-Boveri-Weg, 97074 Würzburg, Germany.

出版信息

J Chem Phys. 2019 Mar 14;150(10):104304. doi: 10.1063/1.5086151.

DOI:10.1063/1.5086151

PMID:30876358

Abstract

We present a theoretical study on exciton-exciton annihilation (EEA) in a molecular dimer. This process is monitored using a fifth-order coherent two-dimensional (2D) spectroscopy as was recently proposed by Dostál et al. [Nat. Commun. 9, 2466 (2018)]. Using an electronic three-level system for each monomer, we analyze the different paths which contribute to the 2D spectrum. The spectrum is determined by two entangled relaxation processes, namely, the EEA and the direct relaxation of higher lying excited states. It is shown that the change of the spectrum as a function of a pulse delay can be linked directly to the presence of the EEA process.

摘要

我们提出了一个关于分子二聚体中激子-激子湮灭（EEA）的理论研究。最近 Dostál 等人 [Nat. Commun. 9, 2466 (2018)] 提出了使用五阶相干二维（2D）光谱来监测这一过程。我们使用每个单体的电子三能级系统，分析了对 2D 光谱有贡献的不同路径。该光谱由两个纠缠的弛豫过程决定，即 EEA 和较高激发态的直接弛豫。结果表明，作为脉冲延迟函数的光谱变化可以直接与 EEA 过程的存在联系起来。