Center for Excitonics
Seminar Series Announcement
The Center for Excitonics is an Energy Frontier Research Center funded by
the
U.S. Department of Energy, Office of Science and Office of Basic Energy
Sciences
The Center for Excitonics invites you to join us at the next seminar of
the
Spring 2010 series. Please forward this information on to others who
might be
interested in attending this and other center seminars.
Title: Quantum Transport Effects and Coherent Ultrafast
Multidimensional
Spectroscopy of Light Harvesting Photosynthetic Complexes
Presenter: Shaul Mukamel
Organization: Department of Chemistry, University of California,
Irvine
Date: March 16, 2010
Time: 3:00 - 4:00pm
Place: Haus Room 36-428
Center URL:
http://www.rle.mit.edu/excitonics
Seminar URL:
http://www.rle.mit.edu/excitonics/mukamel-031610.html
Abstract
The harvesting of solar energy and its conversion to chemical energy is
essential for all forms of life. Whether quantum effects persist in the
energy transport is under active debate. If confirmed, these may explain
the high efficiency of light harvesting and open up applications to
quantum computing and information processing stemming from entanglement of
chromophores. Exciton dynamics simulations in the photosynthetic reaction
center of photosystem II based on a novel quantum exciton dissipation
theory clearly establish oscillatory energy transport at room temperature
originating from interference of quantum pathways. These may be observed
through temporal oscillations of time-resolved two dimensional coherent
optical spectra. Our simulations reveal that quantum energy transfer
effects may persist over the energy transport timescale at room
temperature despite the rapid decoherence effects due to environment
fluctuations. The response of photosynthetic light harvesting complexes to
sequences of femtosecond optical pulses provides multidimensional
snapshots of their structure and electronic dynamics. Two-dimensional
(2D) signals show characteristic cross-peak patterns which carry
information about structures, fluctuations and the entire pathways of
energy and charge transfer. The signals reveal couplings between
chromophores, and quantum coherence signatures of chromophore
entanglement. Coherent quantum pathways and incoherent energy hopping
processes may be resolved. Future extensions of multidimensional
techniques to the attosecond regime using x-ray pulses will be discussed.
Since core excitations are highly localized at selected atoms such signals
can monitor the motions of valence electron wavepackets in real space with
atomic spatial resolution. Common principles underlying coherent
spectroscopy techniques for spins, valence electrons, and core electronic
excitations, spanning frequencies from radiowaves to hard X-rays will be
discussed.
“Coherent Multidimensional Optical Probes for Electronic Correlations and
Exciton Dynamics; from NMR to X-rays”, S. Mukamel, D. Abramavicius, L.
Yang, W. Zhuang, I.V. Schweigert and D. Voronine. Acct.Chem.Res.
Acct.Chem.Res. 42, 553-562 (2009).
“Coherent Multidimensional Optical Spectroscopy Excitons in Molecular
Aggregates; Quasiparticle vs. Supermolecule Perspectives”, D.
Abramavicius, B. Palmieri, D. Voronine, F. Sanda and S. Mukamel, Chem.
Rev. 109, 2350-2408 (2009).
“Coherent Multidimensional Vibrational Spectroscopy of Biomolecules;
Concepts, Simulations and Challenges”. W. Zhuang, T. Hayashi and S.
Mukamel, Agnew Chem. Int.Ed. 48, 3750-3781 (2009).
Bio
Shaul Mukamel received his B.Sc degree in Chemical Physics in 1969 and his
Ph.D. in 1976 both from Tel Aviv University. He served on the faculty of
the Weizmann Institute and Rice University and in 1982 he joined the
chemistry department of the University of Rochester and became a professor
in 1985. In 2000 he became the Kenneth Mees Professor and in 2003 was
appointed joint Professor of Physics. Since 2003 he serves on the faculty
of UC Irvine as a Chancellor Professor of Chemistry.
Professor Mukamel's group interests focus on the design of novel ultrafast
multidimensional coherent optical spectroscopies for probing and
controlling electronic and vibrational molecular dynamics in the condensed
phase; Theoretical and computational studies and applications include
attosecond nonlinear x-ray spectroscopy of molecules; Many-body theory of
optical and photonic materials; a time dependent reduced density matrix
framework for computing electronic excitations and nonlinear optical
spectroscopy of conjugated polymers, molecular nanostructures, chromophore
aggregates and semiconductor and solar cell nanoparticles; Folding and
dynamical fluctuations in proteins and DNA; Long range electron transfer,
energy funneling, and collective nonlinear optical response of biological
light harvesting complexes; Photon statistics in single molecule
spectroscopy; Nonlinear dynamics and fluctuations in quantum and classical
optical response.
Mukamel is a Fellow of the American Physical Society and the Optical
Society of America. He is the recipient of the Alfred P. Sloan, the
Guggenheim, the Alexander von Humboldt Senior Scientist Award and the 2003
Lippincott award of the OSA.