Seminar

Collective Excitations in Biological Antenna Complexes and Dendrimeric Supramolecules

Professor Vladimir Chernyak
Department of Chemistry
University of Rochester

Monday, December 6, 1999
3:00 pm
3269 Beckman Institute

Abstract

The interplay of coherent and incoherent electronic energy transfer and vibrational relaxation in photosynthetic complexes is investigated. The relevant coherence sizes of electronic and nuclear motions and their signatures in femtosecond optical spectroscopy are identified. Applications are made to cooperative spontaneous emission (superradiance), fluorescence, absorption, pump-probe and photon echo spectroscopies in the light-harvesting antenna LH2 of purple bacteria. Localization of optical excitations in artificial antennae (phenylacetylene dendrimers) provides spectroscopic signatures of well-established trends in chemical reactivity. The density of states and optical signals in dendrimers reflect their Cayley-tree geometry.

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