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Title: Interference of interchromophoric energy-transfer pathways in π-conjugated macrocycles

The interchromophoric energy-transfer pathways between weakly coupled units in a π-conjugated phenylene–ethynylene macrocycle and its half-ring analogue have been investigated using the nonadiabatic excited-state molecular dynamics approach. To track the flow of electronic transition density between macrocycle units, we formulate a transition density flux analysis adapted from the statistical minimum flow method previously developed to investigate vibrational energy flow. Following photoexcitation, transition density is primarily delocalized on two chromophore units and the system undergoes ultrafast energy transfer, creating a localized excited state on a single unit. In the macrocycle, distinct chromophore units donate transition density to a single acceptor unit but do not interchange transition density among each other. We find that energy transfer in the macrocycle is slower than in the corresponding half ring because of the presence of multiple interfering energy-transfer pathways. Finally, simulation results are validated by modeling the fluorescence anisotropy decay.
Authors:
 [1] ; ORCiD logo [2] ;  [3] ;  [4] ; ORCiD logo [2] ;  [1]
  1. Univ. Nacional de Quilmes/CONICET, Bernal (Argentina)
  2. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
  3. Technische Univ. Munchen, Garching (Germany)
  4. Univ. Regensburg, Regensburg (Germany)
Publication Date:
Report Number(s):
LA-UR-16-28929
Journal ID: ISSN 1948-7185
Grant/Contract Number:
AC52-06NA25396
Type:
Accepted Manuscript
Journal Name:
Journal of Physical Chemistry Letters
Additional Journal Information:
Journal Volume: 7; Journal Issue: 23; Journal ID: ISSN 1948-7185
Publisher:
American Chemical Society
Research Org:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
OSTI Identifier:
1352374