HERE participant uses computational chemistry methods to simulate chemical separations Meet Stephen Jon Quiton

Oak Ridge National Laboratory (ORNL) had been on Stephen Jon Quiton’s radar since his high school days, when he visited the lab for a summer camp focused on computational physics.

Now an undergraduate at the University of Southern California studying chemical engineering, Quiton recently returned to the U.S. Department of Energy’s largest science and energy laboratory for a 10-week internship through the Higher Education Research Experiences (HERE) Program.

quinton-2.jpg

During his internship at Oak Ridge National Laboratory, undergraduate student Stephen Jon Quiton used quantum chemical computations to simulate the separation of two heavy elements. 

The HERE program at ORNL provides opportunities for students, recent graduates and faculty to participate in research and technical projects under the guidance of ORNL scientists and engineers. HERE utilizes the unique resources of ORNL and encourages careers in the science, technology, engineering and mathematics (STEM) and support fields.

For Quiton, a student interested in engineering, mathematics and chemistry and how these fields intersect, ORNL immediately stood out with its world-class computing facilities and its emphasis on energy and materials. Plus, an internship at ORNL offered an opportunity to gain research experience outside a university setting.

For his HERE internship, Quiton was part of the Chemical Separations Group in ORNL’s Chemical Sciences Division. Under the mentorship of Vyacheslav Bryantsev, Ph.D., Quiton used quantum chemical computations to simulate the separation of two heavy elements found at the bottom of the periodic table: americium and europium.

Such research has important applications to nuclear energy, specifically spent nuclear fuel. As Quiton explained, spent nuclear fuel contains minor actinides, which include americium. Minor actinides are highly radiotoxic relative to other parts of the fuel. These actinides have a high storage volume, presenting significant problems when attempting to store nuclear waste in long-term repositories. Additionally, minor actinides can be reused to produce more nuclear energy.

To separate americium and europium, scientists use a chemical compound that contains nitrogen and carboxylate groups, which allows it to bind to americium, making it easier for extraction.

Although these compounds are being considered for use in nuclear waste separations, recent research has focused on making ligands that can perform the process better. Ligands refer to a molecule that binds to a metal ion through coordinate bonds. However, how these ligands interact with heavy metals, such as americium and other actinides, is not well understood because of a lack of practical computational protocol to describe such compounds reliably.

At ORNL, scientists are testing multiple quantum chemistry methods to determine which can describe the ligand best while minimizing the computational resources expended. They can determine how accurate a given method is by comparing predicted values to experimental results. For Quiton, however, such experimental data was not available for the ligand he was studying, as another group from Idaho National Laboratory was working at the same time to get those results. “This particular ligand was special in that we get to see if computational methods can truly predict experimental values, whereas other ligands that our group studied usually had experiments done before computations,” he said.

quinton.jpg

Stephen Jon Quiton presents during the Ignite-Off competition. (Genevieve Martin/ORNL)

Going forward, the computational methods Quiton used to study his assigned ligand will be repeated for several other compounds and will also be compared to incoming experimental data.

During his internship, in addition to picking up technical skills in areas such as programming, Quiton learned how to manage his time and stay organized.

“The goals for my project involved plenty of data gathering, and even with powerful computers such as the ones I used, jobs can still take upwards of a week or more to finish. Thus, it was absolutely critical to not waste time,” he said. “… And although it was important to be careful and thorough in planning, I always had to check myself to make sure I was not drowning in the details and that I was actually putting my fingers to the keyboard. It was learning to find this balance that revealed the pace I work best at, which will definitely come in handy for future opportunities.”

Quiton also had the chance to hone his public speaking skills. He participated in the second annual Argonne vs. Oak Ridge Ignite-Off. In the Ignite-Off competition, undergraduate and post-bachelor’s interns from Argonne National Laboratory and ORNL summarized their research in five-minute, 20-slide Ignite talks. Later, Quiton shared his research findings with the Chemical Separations Group.

Quiton plans to graduate with a bachelor’s degree in chemical engineering and applied/computational mathematics. He intends to attend graduate school to pursue a doctoral degree and eventually conduct research in computational sciences.

“I would absolutely recommend the HERE program,” Quiton said. “What you will find at ORNL are world-class researchers to connect with and world-class facilities at your disposal. It’s the ultimate center for science nerds, and just to be around them is a valuable experience in itself.”

The HERE program at ORNL is administered by the Oak Ridge Institute for Science and Education (ORISE) for the U.S. Department of Energy.