Theoretical physical chemistry speeds up, slows down reactions for much closer study
May 25, 2017   //   By:   //   Research and Academics

Gary Hoffman said he works with “nerdy stuff.” The close study of diatomic molecules. Applying physics to chemical systems. Building cluster computers to handle enormous calculations.

Hoffman is a theoretical physical chemist. Rather than work at a “wet bench,” handling expensive and potentially volatile chemicals, the professor of chemistry and department chair at Elizabethtown College, simulates reactions, via computer.

Physical chemistry is the application of physics to chemical systems, “how molecules interact with each other,” he said. The theoretical side means he works with enormous equations and, of course, theory, applying known physical laws to determine end results.

Dunham expansion. Newton’s laws of motion. Quantum mechanics.

Theoreticians look at potential compounds to see their reaction rather than waiting for trial and error.

Wet bench research can give inconclusive results. They also can be expensive and, literally, explosive. Hoffman, on the other hand, takes information already known about certain molecules and calculates what will happen as other parameters or chemicals are introduced all via programming. Rather than years or decades of waiting for a result, his calculations are run through cluster computers, taking just hours or days to predict what will take place. Hoffman builds the computers himself to solve the intricate equations.

Often, Hoffman said, it’s necessary to modify reactions, increase temperatures and add various chemicals at different rates. That’s when computer computations can save time, money and potentially lives. Not only that, but a theoretician not only can see what happens in the end, he or she can tell why it occurs and what actually is going on.

E-town students use Hoffman’s computers and modeling software for their integrated laboratory work and in his physical chemistry courses giving them a leg up on graduates from other colleges and universities.

Beyond the classroom, Hoffman said, “a lot of drug companies hire theorists, as do national laboratories, petroleum companies, defense industry leaders and the Department of Energy.”

Hoffman’s specialty is electronic structure theory; a recent project involves diatomic molecules, which are composed of only two atoms. The atoms can be the same—homonuclear—or different chemical elements–heteronuclear.

Sometimes when making observations, Hoffman said a reaction can occur too quickly for a scientist to observe what is going on.  A computer, however, can slow a reaction down to a point where extremely quick changes can be observed.

“Theoreticians look at potential compounds to see their reaction rather than waiting for trial and error. It’s the WHY behind how things happen,” Hoffman said. “We can look at any chemical system and deduce its properties. We can work with very dangerous chemicals but on a computer. … It’s playing with mathematics. It’s exciting to me.”

About the Author :

E.A. (Elizabeth) Harvey is the communications manager and news editor at Elizabethtown College. She has worked in the Office of Marketing and Communications since 2008, after more than two decades as a newspaper feature writer. She holds a bachelor's degree in corporate communication from Elizabethtown College.