Crystallography Made Easier

Crystallographers spend their time solving problems and answering questions about much more than crystals. Using x-ray and neutron diffraction data, they work to determine the arrangement of atoms within solid specimens — an act of detective work that is far from easy.

Crystallographers, also referred to as structural scientists, can have backgrounds in chemistry, physics, geology, material science, biology or other sciences. No matter the field though, all crystallographers encounter difficulties with the samples they are studying.

Drs. Branton Campbell and Harold Stokes of the Department of Physics and Astronomy recently developed a web application for crystallographers that helps them solve and interpret crystal symmetry changes occurring during phase transformations. Their web application interfaces with commercial software to solve the atomic structures of crystals from x-ray diffraction data using group theory.

Group theory is an abstract mathematical construct that explains the behavior of repeating mathematical groups. Although group theory is used widely in many fields, it is somewhat foreign to many crystallographers who find group theory difficult to use. This provided an opportunity for Campbell and Stokes. Campbell, a material scientist himself, collaborated with Stokes, a computational physicist who had studied algorithms for 25 years, to develop the new web application.

“When I found out Harold was a leader in the field, I told him, ‘You’ve got really neat stuff here, but the tools are too hard to use,’” Campbell said. “Collaboration took off from there.”

In the past, software of this nature required users to type in commands from a keyboard. By contrast, the application developed by Campbell and Stokes presents a friendly graphical user interface (GUI), such as those now commonly Campbell-Brandton-007-e1309289995649used in computers and iPods.

“The application lets others use group theory without actually requiring knowledge of it,” Stokes said. “This allows exploration of the difficult concept in a friendly atmosphere.”

For crystallographers, GUIs with drop down boxes and choices are much easier to use than command software. If errors arise, crystallographers can go back and change their selections without having to worry about inputting the wrong text.

Traveling to various corners of the world, Campbell and Stokes have contributed to several crystallography workshops. In May, scientists from around the world gathered in New Orleans, La. to hear a presentation by Campbell and Stokes at the Annual Meeting of the American Crystallography Association.

“We show them how to use the software and get feedback about what they don’t understand,” Stokes said.

The two have also presented the software to crystallographers in Lekeitio, Spain; Osaka, Japan; and Florence, Italy. Later this year, they will present in Madrid, Spain and Karlsruhe, Germany.

“Interest is definitely picking up,” Dr. Campbell said. “Lots of people are interested because now we have made [group theory] accessible.”

By Alysa Kleinman Posted on