Shared vibrations: How photosynthetic light harvesting approaches 100% efficiency

Date: 
Monday, November 17, 2014 -
4:00pm to 5:00pm
Speaker: 
David Jonas
Speaker's Institution: 
University of Colorado

In photosynthesis, light is harvested by antenna proteins that can transfer the electronic excitation energy to a reaction center with near unit quantum efficiency.  The remarkable efficiency of these energy transfer processes has been a mystery for over 50 years, and recent two-dimensional (2D) spectroscopy experiments have found signatures attributed to electronic coherence; it is puzzling that these signatures persist for longer than the apparent energy transfer timescale.   We have recently shown that intramolecular vibrations shared across pigments can drive electronic energy transfer beyond the Born-Oppenheimer framework developed by Forster.  Such shared vibrations on the ground electronic state of the antenna generate all of the observed 2D signatures and their properties reveal the design principle for the antenna.  There are indications that this new mechanism may be operative in a variety of antenna proteins using 5 different photosynthetic pigments.

 

Reference:  PNAS vol. 110, p.1203-1208 (2013)