4 Los Alamos scientists honored by American Association for the Advancement of Science

Scientific achievements noted in national security, chemistry, fuel cells and optoelectronics

January 31, 2023

Stosh Kozimor, Rangachary Mukundan, Tanja Pietrass and Sergei Tretiak.

Four Los Alamos scientists have been named fellows of the American Association for the Advancement of Science. Members have been awarded this honor by AAAS because of their scientifically or socially distinguished efforts to advance science or its applications. The honorees are Stosh Kozimor, Rangachary Mukundan, Tanja Pietrass and Sergei Tretiak.

“For Mukund, Sergei, Stosh and Tanja, this recognition as an AAAS fellow speaks to the important contributions they have each made in their disciplines and to the Laboratory,” said Deputy Director for Science, Technology & Engineering John Sarrao. “Their achievements are a result of their commitment to hard work, collaboration and ingenuity and have been invaluable in helping the Laboratory advance its national security and scientific mission.”

The new AAAS fellows for Los Alamos are the following:

Stosh Kozimor, honored for seminal contributions that have advanced fundamental science and solved applied problems in heavy-element chemistry, separations, isotope production and national security. A scientist in the Laboratory’s Chemistry Division, Kozimor serves as principal investigator for the Office of Science Heavy Element Chemistry Program and works with the Isotope Production team at Los Alamos. He received his doctoral degree in inorganic chemistry from the University of California, Irvine. He originally joined the Laboratory as a Distinguished Frederick Reines fellow. Together with his team, he has advanced fundamental science at the convergence of radio- and inorganic chemistry and has solved technical problems critical to DOE missions in national security, isotope production, separations and heavy-element chemistry.

Rangachary Mukundan, honored for seminal contributions to the development of mixed potential electrochemical sensors and the development of accelerated stress tests for polymer electrolyte membrane fuel cells. He is currently a senior scientist in the Energy Technology area at Lawrence Berkeley National Laboratory and also a guest scientist at Los Alamos, having worked for 25 years at Los Alamos through September 2022. His research interest includes fuel cells, electrolyzers, flow batteries and sensors. His current projects are focused on the durability of polymer electrolyte membrane electrolyzers and fuel cells. He is the co-inventor on eight U.S. patents and has authored more than 190 peer-reviewed journal and transaction papers, cited more than 10,000 times. Mukundan received his doctoral degree in materials science and engineering from the University of Pennsylvania.

Tanja Pietrass, honored for distinguished leadership in academe and government and at Los Alamos National Laboratory, developing and implementing strategic goals while ensuring a respectful and inclusive work environment. Pietrass is the director of the Capability Integration Program Office at Los Alamos in the Associate Directorate for Weapons Physics. Before her current role, Pietrass served as the division leader for the Materials Physics and Applications and Physics divisions. She is a member of the federal government’s Senior Executive Service and served as the Department of Energy’s Division Director of Chemical Sciences, Geosciences, and Biosciences and as the deputy and acting Division Director of the National Science Foundation’s Chemistry Division. She started her career as an assistant professor at New Mexico Tech in 1995 and then became a full professor. Pietrass earned a doctorate (summa cum laude) in chemistry from the Technical University in Munich, Germany, and completed her training as postdoctoral scholar at the University of California, Berkeley, and the Université Louis Pasteur in Strasbourg, France.

Sergei Tretiak, honored for distinguished contributions to the field of computational and theoretical chemical physics, especially for optical materials for next-generation energy systems, electronic properties of molecular structures and optoelectronics of low-dimensional materials. Tretiak is a Laboratory Fellow in the Theoretical Division at Los Alamos. He received his Chemistry doctorate from the University of Rochester. He was then a postdoctoral fellow, and subsequently became a staff scientist at Los Alamos and a member of the Department of Energy-funded Center for Integrated Nanotechnologies. He became an American Physical Society fellow and a fellow of the Royal Society of Chemistry. He has also received the Humboldt Research Award, the Los Alamos Postdoctoral Distinguished Mentor Award and the Los Alamos Fellow’s Prize for Research. Tretiak has published more than 400 articles, been cited nearly 30,000 times and presented more than 300 invited and keynote talks in the United States and abroad. 

AAAS has awarded the distinction of fellow to 506 of its members this year. New fellows will be presented with an official certificate and a gold and blue (representing science and engineering, respectively) rosette pin during the AAAS Annual Meeting.

About AAAS

The American Association for the Advancement of Science (AAAS) is the world’s largest general scientific society and publisher of the journal Science, as well as Science Translational Medicine; Science Signaling; a digital, open-access journal, Science Advances; Science Immunology; and Science Robotics. AAAS was founded in 1848 and includes more than 250 affiliated societies and academies of science, serving 10 million individuals. Science has the largest paid circulation of any peer-reviewed general science journal in the world. The nonprofit AAAS is open to all and fulfills its mission to “advance science and serve society” through initiatives in science policy, international programs, science education, public engagement and more.