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Title: Optical probes of the quantum-entangled triplet-triplet state in a heteroacene dimer
The nature and extent of the spin-entanglement in the triplet-triplet biexciton with total spin zero in correlated-electron π-conjugated systems continues to be an enigma. Differences in the ultrafast transient absorption spectra of free triplets versus the triplet-triplet can give a measure of the entanglement. This, however, requires theoretical understandings of transient absorptions from the optical spin-singlet, the lowest spin-triplet exciton, as well as from the triplet-triplet state, whose spectra are often overlapping and hence difficult to distinguish. We present a many-electron theory of the electronic structure of the triplet-triplet, and of complete wavelength-dependent excited state absorptions (ESAs) from all three states in a heteroacene dimer of interest in the field of intramolecular singlet fission. The theory allows direct comparisons of ESAs with existing experiments as well as experimental predictions, and gives physical understandings of transient absorptions within a pictorial exciton basis that can be carried over to other experimental systems.  more » « less
Award ID(s):
1764152
NSF-PAR ID:
10098344
Author(s) / Creator(s):
;
Date Published:
Journal Name:
Physical review. B, Condensed matter
Volume:
98
Issue:
16
ISSN:
1095-3795
Page Range / eLocation ID:
165202
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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