Public Release: 

Argonne chemist wins national award for studies of plant energy

American Chemical Society

Marion C. Thurnauer of Downer's Grove, Ill., will be honored April 9 by the world's largest scientific society for her contributions to research into photosynthesis, the process by which plants derive chemical energy, their "food," from sunlight. She will receive the 2002 Francis P. Garvan-John M. Olin Medal from the American Chemical Society at its national meeting in Orlando, Fla.

Thurnauer's insights into plants and chlorophyll, the light-absorbing molecule that makes vegetation green, has potential impact on research as diverse as breaking down hazardous waste into harmless compounds and perhaps even repairing faulty DNA.

The key is keeping the energy transfer moving forward, said Thurnauer, who is a biophysical chemist at Argonne National Laboratory in Illinois. Her work focuses on the earliest steps of photosynthesis, the process that converts light into chemical energy to drive the growth, repair and reproduction of plants.

"The first reaction to take place is a separation of electrical charge," she said. "Light is absorbed, the energy excites the chlorophyll molecules, and a fast electron transfer sets up the charge separation."

Intrigued, Thurnauer and her team then made a laboratory version of the energy "pump" that keeps the negatively charged electrons away from the positively charged "holes" they leave behind. Moving electrons in a controlled manner can be a way to chemically neutralize toxic compounds, for example.

Their laboratory system uses nanocrystalline particles of metal oxides. As light pumps energy into a particle, electrons from molecules attached to the surface of the particle can move into the particle. The greater the distance between the excited electrons and the resulting "holes," the more likely the energy transfer will keep moving forward -- that is, the conversion of light to chemical energy.

Thurnauer, whose aunt became a physicist in the days when few women were in science, said "family influence" led her to choose a scientific career as well. The excitement comes in "the ability to discover something that -- for one moment -- is entirely your own," she said. "It's very creative."

She received her undergraduate degree in 1968 and her Ph.D. in 1974 from the University of Chicago.

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The ACS Francis P. Garvan-John M. Olin Medal is sponsored by WCC.

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