Inhomogeneous Broadening Induced Long-Lived Integrated Two-Color Coherence Photon Echo Signal

Journal Article · Thu Jul 31 04:00:00 EDT 2014 · Journal of Physical Chemistry. B, Condensed Matter, Materials, Surfaces, Interfaces and Biophysical Chemistry

DOI:https://doi.org/10.1021/jp503045z· OSTI ID:1407244

Dong, Hui ^[1]; Fleming, Graham R. ^[1]

---

1. Univ. of California, Berkeley, CA (United States). Dept. of Chemistry; Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

Recent observations of the long-lasting nonlinear signals in a variety of light-harvesting complexes have initiated an active debate on the origin of long-lived coherence in the biological systems. In this work we show that disorder of site energy can induce a long-lived electronic coherence between two chromophores in a strongly coupled dimer system, in addition to the ensemble dephasing effect. This phenomenon is physically explained as the correlated fluctuation of excitons with the equal delocalization on two sites, when the site-energy distributions overlap to give resonance. Using the integrated two-color coherence photon echo signal as an example, we show that the coherence in such a system exhibits a biexponential decay with a slow component with a lifetime of hundreds of femtoseconds and a rapid component with a lifetime of tens of femtoseconds. The current result provides a possible microscopic basis for the electronic coherence to be the origin of the long-lived coherence signals to be considered along with other recently proposed mechanisms.

• Research Organization: Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
• DOE Contract Number: AC02-05CH11231
• OSTI ID: 1407244
• Journal Information: Journal of Physical Chemistry. B, Condensed Matter, Materials, Surfaces, Interfaces and Biophysical Chemistry, Journal Name: Journal of Physical Chemistry. B, Condensed Matter, Materials, Surfaces, Interfaces and Biophysical Chemistry Journal Issue: 30 Vol. 118; ISSN 1520-6106
• Publisher: American Chemical Society
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY