‘Impossible’ molecular chain reaction on metal surface demonstrated

Washington, Dec 12 : A team of scientists at the University of Pittsburgh and the U. S. Department of Energy National Energy Technology Laboratory (NETL) in Pittsburgh has demonstrated a molecular chain reaction on a metal surface – a nanoscale process with sizable potential in areas from nanotechnology to developing information storage technology.

The researchers said that a single electron caused a self-perpetuating chain reaction that rearranged the bonds in 10 consecutive molecules positioned on a gold surface.

As each molecule''s original bond was broken by the reaction, the molecule rearranged itself to form a new molecule.

According to study co-author Kenneth Jordan, a Distinguished Professor of Chemistry in Pitt''s School of Arts and Sciences and codirector of the University''s Center for Simulation and Modeling, the ability to initiate molecular chain reactions and self-assembly has potential applications in information storage and in nanolithography, a process used in producing microchips and circuit boards.

Since the demonstrated reaction involved several molecules on a surface, it reframes researchers'' understanding of surface-based chain reactions.

"The conventional wisdom held that a surface reaction would fizzle soon after the electron was introduced. Our work, however, shows that reactions on metal surfaces can be sustained over long distances," Jordan said.

The researchers worked with dimethyldisulfide molecules—two CH(3) methyl groups bonded by two adjoining sulfur atoms.

The added electron split the bond between the sulfur atoms of one molecule, creating a highly reactive free radical that attacked the sulfur-sulfur bond of the neighboring molecule.

The radical split the bond, resulting in a new molecule and a new radical that proceeded to the sulfur-sulfur bond of the next molecule. The process repeated itself through a series of molecules.

The study is published in the Dec. 12 edition of Science. (ANI).

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