Symmetry-Breaking Manipulated Channel Ergodicity in Intramolecular Singlet Fission Uncovered Statistically by Molecular Dynamics Samplings.

Abstract

Persistent structure dynamics of chromophores in a solvent has a pivotal influence on singlet fission (SF) phenomena through breaking structure symmetry and tuning electronic properties. However, clarifying how the dynamic factors manipulate the SF dynamics faces major challenges. Here, we for the first time propose a dynamic symmetry-breaking strategy for manipulating intramolecular SF and unveil channel-ergodic characters by constructing transient configuration space of an individual solvated monomer in a chromophore-in-solvent ensemble by sampling its dynamics trajectory. Dynamic symmetry-breaking leads an SF ensemble to find possible SF channels (i.e., subensembles), characterized by a broad energy population of a charge-transfer state and its coupling with a locally excited state, and the populated multichannels featuring distinct probability distributions determine the dominant SF mechanism and also reveal channel conversion and ergodic behavior, agreeing highly with experimental observations. This work emphasizes the vital role of the inherent structure dynamics of a chromophore in solvent in manipulating such photophysics characteristics by evaluating their symmetry-breaking properties statistically.