The role of vibronic coupling in the electronic spectroscopy of maleimide: a multi-mode and multi-state quantum dynamics study
The role of vibronic coupling in the electronic spectroscopy of maleimide: a multi-mode and multi-state quantum dynamics study
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DOI：
10.1039/d0cp04514d
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发表时间：
2020-11-21
影响因子：
3.3
通讯作者：
Worth, Graham A.
中科院分区：
文献类型：
--
作者：
Lehr, Andreas;Gomez, Sandra;Worth, Graham A.
使用哈密顿量模型研究了马来酰亚胺电子吸收光谱中低于 7 eV 的前两个激发带，该哈密顿量模型包括 24 种振动模式流形内的 4 个低位单重激发态。研究了非绝热效应的作用，并阐明了宽广的、以状态间耦合为主的光谱带以及精细结构的、不太强的耦合光谱带。使用多配置瞬态 Hartree (MCTDH) 波包传播方法及其多层版本 (ML-MCTDH) 进行计算，该方法使用二次振动耦合 (QVC) 哈密顿模型，其中参数是通过从头算方法计算的拟合绝热势能面获得的。量子动力学计算提供了有关弛豫动力学和所涉及的振动模式的信息。已经有了低阶电子振动耦合模型并且仅考虑了几种模式，就获得了与实验光谱的定量一致性。然而，我们发现需要考虑所有模式才能全面了解该分子的光激发弛豫动力学。
The first two excitation bands below 7 eV in the electronic absorption spectrum of maleimide are investigated using a model Hamiltonian including four low-lying singlet excited states within the manifold of 24 vibrational modes. The role of non-adiabatic effects is studied and shines light on both the broad, inter-state coupling-dominated spectral band as well as the fine-structured, not-so-strong coupled band. Calculations have been performed using the Multiconfigurational Time-Dependent Hartree (MCTDH) wavepacket propagation method as well as its multilayer version (ML-MCTDH) using a quadratic vibronic coupling (QVC) Hamiltonian model where parameters are obtained from fitting adiabatic potential energy surfaces computed by ab initio methods. The quantum dynamics calculations provide information on the relaxation dynamics and the vibrational modes involved. Already with a low-order vibronic coupling model and only a few modes being considered, a quantitative agreement with the experimental spectrum is obtained. However, it is found that all modes need to be considered to get a full picture of the photo-excited relaxation dynamics of this molecule.