论文标题
使用插值图建模有机晶体中的非局部电子偶联：晶体五烯的光谱和7,8,15,16-16-Tetraazaterrylene
Modeling Nonlocal Electron-Phonon Coupling in Organic Crystals Using Interpolative Maps: The Spectroscopy of Crystalline Pentacene and 7,8,15,16-Tetraazaterrylene
论文作者
论文摘要
电子 - 音波耦合在有机晶体的传输特性和光体物理学中起着核心作用。这些系统中描述电荷和能量传输的成功模型通常包括这些效果。另一方面，大多数用于描述光物理学的模型仅结合了分子内振动模式的局部电子 - 音波耦合，而非局部电子 - phonon耦合被忽略了。人们可能会期望非局部耦合对有机晶体的光体物理产生重要影响，因为它在电荷转移耦合中会引起大波动，并且电荷转移耦合在许多有机晶体的光谱中起着重要作用。在这里，我们研究了非局部耦合对晶体五烯和7,8,15,16-苯丙烯的吸收光谱的影响。为此，我们开发了一种新的混合量子古典方法，用于在有机晶体的光谱和传输模型中包含非局部耦合。重要的是，我们的方法并不认为与大多数现代电荷传输模型相比，非局部耦合是线性的。我们发现，非局部耦合在吸收线形状上不均匀地拓宽了吸收光谱。例如，在五苯烯中，我们的模型预测，下davydov的下部成分比上戴维多夫上部的组件宽大得多，这是第一次解释了这种实验性观察的起源。通过研究一个简单的二聚体模型，我们能够将这种选择性扩展归因于电荷转移耦合的波动之间的相关性。总体而言，我们的方法将非局部电子音波耦合融合到具有计算效率的光谱和传输模型中，对广泛的有机晶体的概括性以及没有任何线性假设。
Electron-phonon coupling plays a central role in the transport properties and photophysics of organic crystals. Successful models describing charge- and energy-transport in these systems routinely include these effects. Most models for describing photophysics, on the other hand, only incorporate local electron-phonon coupling to intramolecular vibrational modes, while nonlocal electron-phonon coupling is neglected. One might expect nonlocal coupling to have an important effect on the photophysics of organic crystals, because it gives rise to large fluctuation in the charge-transfer couplings, and charge-transfer couplings play an important role in the spectroscopy of many organic crystals. Here, we study the effects of nonlocal coupling on the absorption spectrum of crystalline pentacene and 7,8,15,16-tetraazaterrylene. To this end, we develop a new mixed quantum-classical approach for including nonlocal coupling into spectroscopic and transport models for organic crystals. Importantly, our approach does not assume that the nonlocal coupling is linear, in contrast to most modern charge-transport models. We find that the nonlocal coupling broadens the absorption spectrum non-uniformly across the absorption line shape. In pentacene, for example, our model predicts that the lower Davydov component broadens considerably more than the upper Davydov component, explaining the origin of this experimental observation for the first time. By studying a simple dimer model, we are able to attribute this selective broadening to correlations between the fluctuations of the charge-transfer couplings. Overall, our method incorporates nonlocal electron-phonon coupling into spectroscopic and transport models with computational efficiency, generalizability to a wide range of organic crystals, and without any assumption of linearity.
