What Can Be Learned from Magnetic Field Effects on Singlet Fission: Role of Exchange Interaction in Excited Triplet Pairs
详细信息 查看全文
- 作者：Masanobu Wakasa ; Mana Kaise ; Tomoaki Yago ; Ryuzi Katoh ; Yusuke Wakikawa ; Tadaaki Ikoma
- 刊名：Journal of Physical Chemistry C
- 出版年：2015
- 出版时间：November 19, 2015
- 年：2015
- 卷：119
- 期：46
- 页码：25840-25844
- 全文大小：268K
- ISSN：1932-7455
文摘
Magnetic field effects (MFEs) on singlet fission were studied by observing fluorescence from organic crystal of 1,6-diphenyl-1,3,5-hexatriene under magnetic fields of up to 5 T. We found anomalous MFE dips at magnetic fields higher than 2 T, in addition to the known MFEs which saturated around 1 T. The observed results were analyzed by using the stochastic Liouville equation (SLE) in which a distance-dependent exchange interaction (J) in triplet pair, hopping of triplet, and geminate fusion in contacted triplet pair were incorporated. The SLE analysis revealed that the observed dips were caused by a MFE due to the level crossing mechanism and strongly suggested that the contacted triplet pair has a large J, which has been ignored in the previous model of MFEs on the singlet fission. Present results lead to the conclusion that the initial dissociation of the singlet exciton to the contacted triplet pair does not show the MFE and the triplet pair at a separated distance produced by hopping of the triplet plays an important role on the generation of the MFE on the singlet fission.