The effect, described in the April 12, 2007 issue of Nature, occurs when light-induced excitations in the complex meet and interfere constructively much like the interactions that occur between the ripples formed by throwing stones into a pond.
The collaboration is a good illustration of interdisciplinary science. The Washington University group's expertise is in photosynthesis, especially antenna systems, and the West Coast group's specialty is advanced laser techniques. The quantum finding would have been impossible without collaboration.
"We have obtained the first direct evidence that remarkably long-lived wavelike electronic quantum coherence plays an important part in energy transfer processes during photosynthesis," said Fleming, the principal investigator for the study. "This wavelike characteristic can explain the extreme efficiency of the energy transfer because it enables the system to simultaneously sample all the potential energy pathways and choose the most efficient one."
Fleming is also a professor of chemistry at UC Berkeley, and an internationally acclaimed leader in spectroscopic studies of the photosynthetic process. In a paper entitled, "Evidence for wavelike energy transfer through quantum coherence in photosynthetic systems," he and his collaborators report the detection of "quantum beating" signals, coherent electronic oscillations in both donor and acceptor molecules, generated by light-induced energy excitations, like the ripples formed when stones are tossed into a pond.
Electronic spectroscopy measurements made on a femtosecond (millionths of a billionth of a second) time-scale showed these oscillations meeting and interfering constructively, forming wav
Source:Washington University in St. Louis