title: Extracting dynamics of excitonic coherences in congested spectra of photosynthetic light harvesting antenna complexes.
abstract: We present an analysis of dephasing rates for multiple zero-quantum electronic coherences in the Fenna-Matthew-Olson (FMO) pigment-protein complex using two-dimensional electronic spectroscopy. We employ the linear prediction Z-transform to determine both the frequency and decay rates of 8 individually assigned exciton-exciton coherences. Despite congestion in the spectra, we can isolate multiple crosspeaks signals and analyze their dephasing rates. A nontrivial relationship exists between the excitons and the bath determining the lifetimes of different exciton-exciton coherences. We propose that the correlations that protect long-lived electronic coherence may yield microscopic knowledge regarding the structure of the protein bath surrounding the chromophores.
authors.affiliation: Department of Chemistry and The James Franck Institute, The University of Chicago, 929 East 57th Street, Chicago, IL, 60637, USA.
authors.forename: Justin R
authors.initials: JR
authors.lastname: Caram
authors.forename: Gregory S
authors.initials: GS
authors.lastname: Engel
mesh_terms: D045342:Light-Harvesting Protein Complexes / Q000737:chemistry* / Q000378:metabolism; D011789:Quantum Theory; D013057:Spectrum Analysis
chemical_list: D045342:Light-Harvesting Protein Complexes