title: Can Excited State Electronic Coherence Be Tuned via Molecular Structural Modification? A First-Principles Quantum Electronic Dynamics Study of Pyrazolate-Bridged Pt(II) Dimers.
abstract: Materials and molecular systems exhibiting long-lived electronic coherence can facilitate coherent transport, opening the door to efficient charge and energy transport beyond traditional methods. Recently, signatures of a possible coherent, recurrent electronic motion were identified in femtosecond pump-probe spectroscopy experiments on a binuclear platinum complex, where a persistent periodic beating in the transient absorption signal's anisotropy was observed. In this study, we investigate the excitonic dynamics that underlie the suspected electronic coherence for a series of binuclear platinum complexes exhibiting a range of interplatinum distances. Results suggest that the long-lived coherence can only result when competitive electronic couplings are in balance. At longer Pt-Pt distances, the electronic couplings between the two halves of the binuclear system weaken, and exciton localization and recombination is favored on short time scales. For short Pt-Pt distances, electronic couplings between the states in the coherent superposition are stronger than the coupling with other excitonic states, leading to long-lived coherence.
authors.affiliation: Department of Chemistry, University of Washington , Seattle, Washington 98195, United States.
authors.forename: David B
authors.initials: DB
authors.lastname: Lingerfelt
authors.affiliation: Department of Chemistry, University of Washington , Seattle, Washington 98195, United States.
authors.forename: Patrick J
authors.initials: PJ
authors.lastname: Lestrange
authors.affiliation: Department of Chemistry, University of Washington , Seattle, Washington 98195, United States.
authors.forename: Joseph J
authors.initials: JJ
authors.lastname: Radler
authors.affiliation: Department of Chemistry, Northwestern University , Evanston, Illinois 60208, United States.
authors.forename: Samantha E
authors.identifier: http://orcid.org/0000-0002-7997-4523
authors.initials: SE
authors.lastname: Brown-Xu
authors.affiliation: Department of Chemistry, Northwestern University , Evanston, Illinois 60208, United States.|Chemical Sciences and Engineering Division, Argonne National Laboratory , Lemont, Illinois 60439, United States.
authors.forename: Pyosang
authors.initials: P
authors.lastname: Kim
authors.affiliation: Department of Chemistry, North Carolina State University , Raleigh, North Carolina 27695-8204, United States.
authors.forename: Felix N
authors.identifier: http://orcid.org/0000-0001-7546-8618
authors.initials: FN
authors.lastname: Castellano
authors.affiliation: Department of Chemistry, Northwestern University , Evanston, Illinois 60208, United States.|Chemical Sciences and Engineering Division, Argonne National Laboratory , Lemont, Illinois 60439, United States.
authors.forename: Lin X
authors.initials: LX
authors.lastname: Chen
authors.affiliation: Department of Chemistry, University of Washington , Seattle, Washington 98195, United States.
authors.forename: Xiaosong
authors.identifier: http://orcid.org/0000-0001-7341-6240
authors.initials: X
authors.lastname: Li