Sandoval-Salinas María E, Carreras Abel, Casado Juan, Casanova David
Departament de Ciència de Materials i Química Física and Institut de Química Teòrica i Computacional (IQTCUB), Universitat de Barcelona, Martí i Franquès 1-11, Barcelona, 08028 Catalunya, Spain.
Donostia International Physics Center (DIPC), Manuel Lardizabal Pasealekua 4, Donostia, Euskadi 20018, Spain.
J Chem Phys. 2019 May 28;150(20):204306. doi: 10.1063/1.5097048.
Spiroconjugation results in a unique arrangement of conjugated fragments providing a novel way to chemically connect chromophoric units and control their electronic interaction, which is a key factor for the viability of the singlet fission photophysical reaction. In this study, we computationally explore the possibility of intramolecular singlet fission in spiroconjugated dimers by characterizing the nature of the low-lying excited electronic states, evaluating the magnitude of interstate couplings, describing possible singlet fission mechanisms, and investigating the potential role of low and high frequency vibrational modes in the exciton fission process. The spiro linkage of organic chromophores with the proper excited singlet and triplet energies favors the presence of low-lying charge resonance states, which play a major role in the formation of the triplet pair state. Overall, our results suggest that spiroconjugated dimers are potentially good candidates to efficiently generate independent triplet states through singlet fission.
螺共轭作用导致共轭片段的独特排列，为化学连接发色团单元并控制它们的电子相互作用提供了一种新方法，这是单线态裂变光物理反应可行性的关键因素。在本研究中，我们通过表征低激发电子态的性质、评估态间耦合的大小、描述可能的单线态裂变机制以及研究低频和高频振动模式在激子裂变过程中的潜在作用，对螺共轭二聚体中分子内单线态裂变的可能性进行了计算探索。具有适当激发单线态和三线态能量的有机发色团的螺键有利于低电荷共振态的存在，这些态在三线态对态的形成中起主要作用。总体而言，我们的结果表明，螺共轭二聚体有可能成为通过单线态裂变有效产生独立三线态的良好候选物。
