Professor Villy Sundstrom
Chemical Center
Lund University
Lund, Sweden

Wednesday, March 11, 1998
3:00 pm (CT)
3269 Beckman Institute

Abstract

Excitation transfer and relaxation has been studied in bacterial LH1 and LH2 complexes, using femtosecond spectroscopy and computer simulations. We conclude that the spectral evolution on the timescale of a few hundred femtoseconds is due to relaxation among the exciton states of the LH rings. Slower spectral evolution on the several picosecond time scale is most likely due to energy transfer among different rings. Carotenoid molecules are traditionally used to probe transmembrane potentials in RC and LH complexes. We have recently discovered a response from the carotenoids of LH2 to optical excitation of B800 or B850. This carotenoid response can be used to monitor the ultrafast excitation dynamics within and between LH complexes.

Tea and coffee will be served in R3151 Beckman Institute at 2:15pm.