Simulation of a superacid.

Understanding Superacids

University of Pennsylvania scientist Michael Klein and his colleague Dongsup Kim have used PSC's CRAY T3E and the prototype Terascale Computing System to develop quantum-level knowledge of superacids. Essential tools of the chemical industry, superacids have a powerful ability to break down raw petroleum, leading to such products as high-strength plastics and lead-free high-octane gasoline. Though industry uses hundreds of thousands of tons of superacid annually, there has been little understanding of how they work chemically.

Through simulations at PSC, Klein and Kim are shedding new light on why some superacids are stronger than others, showing that they form clusters with a ring-like structure, a previously unrecognized key to their chemistry. Their simulations also explained experiments showing that superacids conduct electricity better than can be accounted for by ionic diffusion, the normal process by which electrons in solution roam from ion to ion.

This graphic from Klein's computational study illustrates the details of a mechanism called "proton jumping" that underlies the electrical conductivity of superacids. In the strongest superacid, antimony pentafluoride, an excess proton (yellow) attaches to a fluorine atom (red), and they stay together as they "jump" along a linked chain of hydrogen-fluoride molecules (blue and green). The simulation shows that the proton and its fluorine partner travel across three bonds in 81.5 billion-millionths of a second (10-15 sec.).

Close this window.