Femtosecond stimulated Raman evidence for charge-transfer character in pentacene singlet fission.

ABSTRACT: Singlet fission is a spin-allowed process in which an excited singlet state evolves into two triplet states. We use femtosecond stimulated Raman spectroscopy, an ultrafast vibrational technique, to follow the molecular structural evolution during singlet fission in order to determine the mechanism of this process. In crystalline pentacene, we observe the formation of an intermediate characterized by pairs of excited state peaks that are red- and blue-shifted relative to the ground state features. We hypothesize that these features arise from the formation of cationic and anionic species due to partial transfer of electron density from one pentacene molecule to a neighboring molecule. These observations provide experimental evidence for the role of states with significant charge-transfer ch

SUBMITTER: Hart SM 

PROVIDER: S-EPMC5885776 | biostudies-literature | 2018 Feb

REPOSITORIES: biostudies-literature