Elucidating the dynamics of molecules that are both long-lasting and elusive is the goal of Wilton Virgo, recently named a Martin Luther King Jr. Visiting Scholar.
"Metastability" is molecules' ability to persist for a long time in one chemical state.
Virgo's research focuses on gas molecules in long-lived, highly reactive states called metastable triplet states. "The molecules I study are intriguing because they act as chemical protagonists in reactions initiated either by ultraviolet light or by molecular collisions. I want to illuminate the process of chemical energy flow in the molecule in order to understand the driving force behind chemical reactions," he said.
"Our research investigates how metastable molecules are involved in both intra-molecular and intermolecular energy flow," he said. "This is a major goal of the chemical dynamics field."
In nature, molecules want to be in their most stable, lowest energy state, called the ground state. Usually, excited molecules can give up their energy by emitting light in the form of fluorescence and making a transition to the ground state.
"In our field, metastable states of molecules possess excess electronic energy but cannot dispose of that energy because the transition to the ground state is optically forbidden," Virgo said. The molecule is like a reactive bundle of energy that has no way of getting to the ground state.
"The energy in the molecule can't be lost spontaneously via fluorescence, but it can be used to drive chemical reactions when the excited molecule collides with a normal molecule in its ground energy state. The metastable molecule can give its energy to other molecules via collisions, causing chemical reactions to take place," Virgo said.
Despite their key role in chemical reactions, these molecules can easily elude detection. "My research involves inventing new, sophisticated techniques using lasers, molecular beams and detection of the metastables on metal surfaces," he said.
Virgo arrived at MIT in January 2006 as a postdoctoral associate in the laboratory of Robert W. Field, the Haslam and Dewey Professor of Chemistry.
Virgo earned his undergraduate degree in chemistry at Princeton University. He worked as a professional associate at Brookhaven National Laboratory in 2001 and received his Ph.D. degree from Arizona State University in 2005.
A version of this article appeared in MIT Tech Talk on June 6, 2007 (download PDF).
