Alán Aspuru-Guzik | Professor of Chemistry and Chemical Biology
Harvard University | 12 Oxford Street, Room M113 | Cambridge, MA 02138
(617)-384-8188 |
http://aspuru.chem.harvard.edu |
http://about.me/aspuru
---------- Forwarded message ----------
From: Justin Caram <jcaram(a)mit.edu>
Date: Tue, Jun 23, 2015 at 8:55 AM
Subject: Talk of possible interest to Center for Excitonics
To: "efrc-faculty(a)mit.edu" <efrc-faculty(a)mit.edu>du>,
"excitonics-sp(a)mit.edu" <
excitonics-sp(a)mit.edu>
Hi all,
I invited a former labmate of mine to give an informal talk. It may be of
interest to members of the center. It will be this Friday (June 26) at
11:00 in 6-321 (Moore Room). Here is the abstract.
--Justin Caram
________________________________
Two-Dimensional Electronic Spectroscopy In Highly Scattering Media Reveals
Energy Transfer Events In Living Rhodobacter sphaeroides
Efficient exciton transport over large distances through polymer networks
is an open problem in chemistry with applications to solar harvesting, and
efficient lighting. However, photosynthetic organisms routinely perform
exciton transport over distances greater than 100 nm with nearly 100%
quantum efficiency. Furthermore they exhibit real time control over energy
transfer pathways in order to both optimize light harvesting and protect
the organism from excess excitation. Understanding the design principles
within photosynthetic energy transfer begins with the ability to observe
these ultrafast processes in living organisms. I will present advances in
two-dimensional electronic spectroscopy (2DES) that permit the acquisition
of 2DES signals in the presence of intensely scattered light. These
advances have made possible the observation of energy transfer at room
temperature in living cells of Rhodobacter sphaeroides, a purple bacterium
known for its high quantum efficiency. Timescales of 50 fs - 200 ps are
recovered in a single experiment exhibiting both intra and inter complex
relaxation and transfer. Further 2DES experiments done in fast succession
(~ every 15 min) were performed to capture real time changes to the energy
transfer pathways in response to oxygen and intense light.