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Title: Practical witness for electronic coherences

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Publication Date:
Research Org.:
Energy Frontier Research Centers (EFRC) (United States). Center for Excitonics (CE)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
DOE Contract Number:
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Chemical Physics; Journal Volume: 141; Journal Issue: 24; Related Information: CE partners with Massachusetts Institute of Technology (lead); Brookhaven National Laboratory; Harvard University
Country of Publication:
United States
solar (photovoltaic), solid state lighting, photosynthesis (natural and artificial), charge transport, optics, synthesis (novel materials), synthesis (self-assembly), synthesis (scalable processing)

Citation Formats

Johnson, Allan S., Yuen-Zhou, Joel, Aspuru-Guzik, Alán, and Krich, Jacob J.. Practical witness for electronic coherences. United States: N. p., 2014. Web. doi:10.1063/1.4903982.
Johnson, Allan S., Yuen-Zhou, Joel, Aspuru-Guzik, Alán, & Krich, Jacob J.. Practical witness for electronic coherences. United States. doi:10.1063/1.4903982.
Johnson, Allan S., Yuen-Zhou, Joel, Aspuru-Guzik, Alán, and Krich, Jacob J.. 2014. "Practical witness for electronic coherences". United States. doi:10.1063/1.4903982.
title = {Practical witness for electronic coherences},
author = {Johnson, Allan S. and Yuen-Zhou, Joel and Aspuru-Guzik, Alán and Krich, Jacob J.},
abstractNote = {},
doi = {10.1063/1.4903982},
journal = {Journal of Chemical Physics},
number = 24,
volume = 141,
place = {United States},
year = 2014,
month =
  • The origin of the coherences in two-dimensional spectroscopy of photosynthetic complexes remains disputed. Recently, it has been shown that in the ultrashort-pulse limit, oscillations in a frequency-integrated pump-probe signal correspond exclusively to electronic coherences, and thus such experiments can be used to form a test for electronic vs. vibrational oscillations in such systems. Here, we demonstrate a method for practically implementing such a test, whereby pump-probe signals are taken at several different pulse durations and used to extrapolate to the ultrashort-pulse limit. We present analytic and numerical results determining requirements for pulse durations and the optimal choice of pulse centralmore » frequency, which can be determined from an absorption spectrum. Our results suggest that for numerous systems, the required experiment could be implemented by many ultrafast spectroscopy laboratories using pulses of tens of femtoseconds in duration. Such experiments could resolve the standing debate over the nature of coherences in photosynthetic complexes.« less
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  • Described is the polarization controlled two-color coherence photon echo studies of the reaction center complex from a purple bacterium Rhodobacter sphaeroides. Long-lived oscillatory signals that persist up to 2 ps are observed in neutral, oxidized, and mutant (lacking the special pair) reaction centers, for both (0,0,0,0) and (45,-45,90,0) polarization sequences. We show that the long-lived signals arise via vibronic coupling of the bacteriopheophytin (H) and accessory bacteriochlorophyll (B) pigments that leads to vibrational wavepackets in the B ground electronic state. Fourier analysis of the data suggests that the 685 cm -1 mode of B may play a key role inmore » the H to B energy transfer.« less