Brey Dominik, Binder Robert, Martinazzo Rocco, Burghardt Irene
Institute of Physical and Theoretical Chemistry, Goethe University Frankfurt, Max-von-Laue-Str. 7, 60438 Frankfurt am Main, Germany.
Department of Chemistry, Università degli Studi di Milano, Via Golgi 19, 20133 Milano, Italy.
Faraday Discuss. 2022 Sep 15;237(0):148-167. doi: 10.1039/d2fd00014h.
Two-dimensional electronic spectroscopy (2DES) signals for homo-oligomer J-aggregates are computed, with a focus on the role of structural change induced by low-frequency torsional modes, along with quasi-stationary trapping effects induced by high-frequency polaronic modes. To this end, a model system is derived from an parametrized site-based Hamiltonian for oligothiophenes [Binder , , 2018, , 227401]. To obtain a compact representation, we introduce a collective lattice mode whose vibronic coupling depends nonlinearly on the exciton density. As a result, an -site model with a single polaronic mode and a single torsional mode is obtained. Furthermore, a quantum-classical treatment is employed where the torsional mode is treated within a mean-field Ehrenfest/Langevin approximation. 2D electronic spectra are computed using the equation-of-motion phase-matching approach (EOM-PMA) within a wavefunction description. It is seen that the spectra combine the vibronic fine structure, due to the polaronic mode, and a dynamic Stokes shift, due to torsional relaxation. The signatures of the coherent effects and adiabatic evolution in the 2DES signals are discussed.
计算了同寡聚体J-聚集体的二维电子光谱（2DES）信号，重点关注低频扭转模式引起的结构变化以及高频极化子模式引起的准静态俘获效应的作用。为此，从基于位点的寡聚噻吩参数化哈密顿量[Binder，，2018，，227401]推导出一个模型系统。为了获得紧凑的表示，我们引入了一种集体晶格模式，其振动电子耦合非线性地依赖于激子密度。结果，得到了一个具有单极化子模式和单扭转模式的N位点模型。此外，采用量子经典处理方法，其中扭转模式在平均场埃伦费斯特/朗之万近似内进行处理。在波函数描述中，使用运动方程相位匹配方法（EOM-PMA）计算二维电子光谱。可以看出，光谱结合了极化子模式引起的振动电子精细结构和扭转弛豫引起的动态斯托克斯位移。讨论了2DES信号中相干效应和绝热演化的特征。
