“We can do a calculation and predict something and then test it out right away,” he says. “Theory and experiment can go hand in hand, and together we can really discover what is going on.”

Hennig developed this collaborative approach while studying for his Ph.D. in physics at Washington University in St. Louis, where he started out doing experimental work. “I liked it, but I really felt I was missing something,” he says. “I wanted to see what was happening on the atomic level.”

Unlike a theoretical physicist, who might concentrate on a single technique, Hennig uses the full suite of tools in the computational tool box—from the ab initio method, which uses only the basic laws of physics, to the Monte Carlo method, which relies on chance to predict the movement of electrons.

“I’m not just trying to understand and perfect one method,” he says. “I’m interested in solving a problem.”

Hennig has looked at structural alloys used in airplanes, how introduced defects change the properties of semiconductors, and the atomic structure of quasicrystals, which hold promise as coatings for satellites because they are usually metallic and very hard, but poor conductors.

“We’re trying to understand how materials behave in different situations—How strong are they? Do they conduct electricity?—based on the structure of the atoms and what the electrons are doing,” he says. “We use quantum mechanics to figure out what the structure really does in these situations.”

Although it often takes decades before a new material enjoys widespread commercial use, the eventual application of a material is never far from Hennig’s mind. He’s interested in materials used in atomic energy, solar cells, hydrogen storage materials, organic solar cells, and organic semiconductors. “A thread that goes through my research is that I like to work on things that will help society in the long run,” he says.

Prof. Hennig's Web page