Giavazzi D, Di Maiolo F, Painelli A
Department of Chemistry, Life Science and Environmental Sustainability, Università di Parma, 43124 Parma, Italy.
Institute of Physical and Theoretical Chemistry, Goethe University Frankfurt, Max-von-Laue-Str. 7, 60438 Frankfurt, Germany.
Phys Chem Chem Phys. 2022 Mar 2;24(9):5555-5563. doi: 10.1039/d1cp05971h.
We investigate the relaxation of a coherently excited molecule in the Redfield approximation. The molecular model, parametrized to describe donor-acceptor dyes that represent a large family of molecules of interest for several applications, accounts for two diabatic electronic states non-adiabatically coupled to a few vibrational coordinates. The proposed approach successfully describes the fast vibrational relaxation, followed by a much slower relaxation towards the ground state, a physically relevant result that is robust . the specific model adopted for the system-bath coupling and the specific (reasonable) choice of the bath spectral density. We demonstrate that, when dealing with more than a single vibration, it is important that each vibration is separately coupled to an independent bath so as to avoid the cross-talking of the modes through their coupling to the same bath. Provided that the overall strength of the electron-vibration coupling is maintained constant, the number of molecular vibrations introduced in the model does not affect the system dynamics, supporting the use of effective and easy models for donor-acceptor dyes accounting for a single coupled vibration.
我们在雷德菲尔德近似下研究相干激发分子的弛豫过程。该分子模型通过参数化来描述供体 - 受体染料，这类染料代表了一大类在多种应用中具有重要意义的分子，它考虑了两个非绝热耦合到几个振动坐标的非绝热电子态。所提出的方法成功地描述了快速的振动弛豫，随后是向基态慢得多的弛豫，这是一个与物理相关且稳健的结果，这得益于为系统 - 浴耦合所采用的特定模型以及对浴谱密度的特定（合理）选择。我们证明，当处理多个振动时，重要的是每个振动都分别耦合到一个独立的浴，以避免模式通过与同一浴的耦合而产生串扰。只要电子 - 振动耦合的整体强度保持恒定，模型中引入的分子振动数量不会影响系统动力学，这支持了使用有效且简单的供体 - 受体染料模型来考虑单个耦合振动。
