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Using fluorescence detected two-dimensional spectroscopy to investigate initial exciton delocalization between coupled chromophores

Schröter, Marco LU ; Pullerits, Tõnu LU and Kühn, Oliver (2018) In Journal of Chemical Physics 149(11).
Abstract

Förster theory describes electronic exciton energy migration in molecular assemblies as an incoherent hopping process between donor and acceptor molecules. The rate is expressed in terms of the overlap integral between donor fluorescence and acceptor absorption spectra. Typical time scales for systems like photosynthetic antennae are on the order of a few picoseconds. Prior to transfer, it is assumed that the initially excited donor molecule has equilibrated with respect to the local environment. However, upon excitation and during the equilibration phase, the state of the system needs to be described by the full density matrix, including coherences between donor and acceptor states. While being intuitively clear, addressing this regime... (More)

Förster theory describes electronic exciton energy migration in molecular assemblies as an incoherent hopping process between donor and acceptor molecules. The rate is expressed in terms of the overlap integral between donor fluorescence and acceptor absorption spectra. Typical time scales for systems like photosynthetic antennae are on the order of a few picoseconds. Prior to transfer, it is assumed that the initially excited donor molecule has equilibrated with respect to the local environment. However, upon excitation and during the equilibration phase, the state of the system needs to be described by the full density matrix, including coherences between donor and acceptor states. While being intuitively clear, addressing this regime experimentally has been a challenge until the recently reported advances in fluorescence detected two-dimensional spectroscopy. Here, we demonstrate using fourth order perturbation theory the conditions for the presence of donor-acceptor coherence induced cross-peaks at zero waiting time between the first and the second pair of pulses. The approach is illustrated for a heterodimer model which facilitates an analytical solution.

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publication status
published
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in
Journal of Chemical Physics
volume
149
issue
11
article number
031835JCP
publisher
American Institute of Physics (AIP)
external identifiers
  • pmid:30243281
  • scopus:85054028092
ISSN
0021-9606
DOI
10.1063/1.5046645
language
English
LU publication?
yes
id
ebd51278-adec-46e9-8df3-6b8d46473b7f
date added to LUP
2018-10-11 07:07:20
date last changed
2020-10-20 02:33:53
@article{ebd51278-adec-46e9-8df3-6b8d46473b7f,
  abstract     = {<p>Förster theory describes electronic exciton energy migration in molecular assemblies as an incoherent hopping process between donor and acceptor molecules. The rate is expressed in terms of the overlap integral between donor fluorescence and acceptor absorption spectra. Typical time scales for systems like photosynthetic antennae are on the order of a few picoseconds. Prior to transfer, it is assumed that the initially excited donor molecule has equilibrated with respect to the local environment. However, upon excitation and during the equilibration phase, the state of the system needs to be described by the full density matrix, including coherences between donor and acceptor states. While being intuitively clear, addressing this regime experimentally has been a challenge until the recently reported advances in fluorescence detected two-dimensional spectroscopy. Here, we demonstrate using fourth order perturbation theory the conditions for the presence of donor-acceptor coherence induced cross-peaks at zero waiting time between the first and the second pair of pulses. The approach is illustrated for a heterodimer model which facilitates an analytical solution.</p>},
  author       = {Schröter, Marco and Pullerits, Tõnu and Kühn, Oliver},
  issn         = {0021-9606},
  language     = {eng},
  number       = {11},
  publisher    = {American Institute of Physics (AIP)},
  series       = {Journal of Chemical Physics},
  title        = {Using fluorescence detected two-dimensional spectroscopy to investigate initial exciton delocalization between coupled chromophores},
  url          = {http://dx.doi.org/10.1063/1.5046645},
  doi          = {10.1063/1.5046645},
  volume       = {149},
  year         = {2018},
}