Molecular probe

A new tool for probing molecular structure on surfaces has been developed by researchers at the University of Illinois at Urbana-Champaign. 

Single molecule absorption spectroscopy can enhance molecular analysis, surface manipulation and studies of molecular energy and reactivity at the atomic level.

“This new measurement method combines the chemical selectivity of optical absorption spectroscopy with the atomic-scale resolution of scanning tunnelling microscopy,” said Martin Gruebele, a professor of chemistry, physics and biophysics and corresponding author of a paper accepted for publication in the journal Nano Letters, and posted on its Web site.

The method literally feels how a molecule changes shape when it absorbs energy.

”Unlike single molecule fluorescence spectroscopy, which is now a commonly used measurement technique, single molecule absorption spectroscopy has been an elusive goal. Single molecules don’t absorb much light, making detection difficult to begin with,” said Gruebele, who also is a researcher at the university’s Beckman Institute for Advanced Science and Technology.