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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 12: Molecular Electronics and Excited State Properties I
CPP 12.4: Vortrag
Montag, 18. März 2024, 17:00–17:15, H 0106
Ab-initio study on the effect of dipolar spin-spin interactions in singlet fission — •R. K. Kathir1, Pedro Coto2, and Michael Thoss1 — 1Institute of Physics, University of Freiburg, Germany. — 2Materials Physics Center (CFM), Spanish National Research Council (CSIC), Spain.
Interactions between triplet pair states are known to play a key role in important chemical processes. An example is singlet fission (SF), a photo-induced multiple exciton generation mechanism in which a singlet excited state transforms into a pair of triplet excitons [1]. Electron paramagnetic resonance experiments have provided evidence that this process involves the participation of singlet and quintet coupled triplet pair states [2,3,4]. In this contribution, we employ ab-initio multi-reference perturbation theory techniques to investigate the effect of the inter-triplet relative orientation, and the strength of the zero field splitting on the SF kinetics. We perform our studies on a series of modified pentacene dimers where the pentacene-like moieties are covalently bonded to a phenylene linker in ortho, meta, and para positions, shown to undergo intra-molecular SF [5]. Our results provide insight into the spin mixing in these systems, in particular regarding the fate of the coupled triplet pair state in SF.
References:
[1] Chem. Rev., 2010, 110, 6891-6936. [2] Nat. Phys., 2017, 13, 176-181. [3] Nat. Phys., 2017, 13, 182-188. [4] Nat Commun., 2017, 8, 15171. [5] S. R. Reddy, et al., J. Phys. Chem. Lett., 2018, 9, 5979-5986.
Keywords: Excited states; Singlet fission; Multi-reference wavefunction methods; Spin spin interaction; organic photovoltaics