Stosh Kozimor, a Los Alamos National Laboratory fellow and scientist in the Inorganic, Isotope, and Actinide Chemistry group, has received the prestigious Glenn T. Seaborg Award for Nuclear Chemistry from the American Chemical Society. The honor recognizes Kozimor’s groundbreaking work in heavy element, isotope production, and radiochemistry, with a focus on advancing understanding of radioactive materials and solving problems in energy, the environment and national security.
“Stosh’s work reaches from the outer edges of the periodic table to some of the nation’s most pressing challenges,” said Srinivas Iyer, associate laboratory director for Chemical, Earth & Life Sciences at Los Alamos. “From discovering new plutonium chemistry to advancing radioisotopes for cancer diagnostics and treatment, he exemplifies the best of Los Alamos science — translating fundamental discoveries into advances for national security and human health. This honor recognizes his scientific achievements and the leadership and mentorship through which he is shaping the next generation of scientists.”
Kozimor is one of only four Los Alamos researchers to win the award; the other winners are David Clark, Darleane Hoffman and Arthur Wahl.
Kozimor is known for his research in inorganic chemistry and radiochemistry and for leading projects that push the boundaries of actinide science. His expertise centers on studying how certain elements (especially actinides) form bonds and interact with other substances. Using a technique called X-ray absorption spectroscopy, Kozimor’s research has helped explain the complex chemistry of f-elements, ranging from understanding fundamental bonding to how elements exist when dissolved in solutions such as water. A representative highlight includes the first bond distance measurements of the element einsteinium.
Another example includes characterizing actinides cations in molten salt matrixes and using the molten salt matrix to evaluate how ions in the actinide outer coordination sphere impact actinide reactivity and bonding.
In general, Kozimor’s experimental studies have shown how some actinides have unique behavior in comparison to other elements on the periodic table. The work is relevant when it comes to separations associated with isotope production, aqueous plutonium processing and radioanalytical chemistry. Kozimor’s work has opened new possibilities in separations science in general and offers opportunities to change how scientists approach purifying one element from another.
Kozimor has made contributions related to renewing interest in using radioactive elements in nuclear medicine. In this field, many chemical characteristics associated with radioactive elements are poorly defined. This makes it difficult to predict how these types of chemicals act inside the human body. Kozimor and his team are addressing this issue by establishing the fundamental chemical properties associated with these types of elements. For example, Kozimor’s group was the first to study how actinium, a promising candidate for cancer treatment, behaves in solutions. Their research found that actinium prefers certain types of chemical bonds. These results may inform others on how to develop better medicines by designing molecules that match their unique properties.
Kozimor and his colleagues also pioneered a method to make and purify many radionuclides that have application in radiotherapy and radiodiagnostics; the tellurium-119m/antimony-119 pair and the cerium-134 radionuclides are representative examples. Before their work, there were no ways to produce large quantities of these radioisotopes for hospitals. Kozimor and his team overcame these technical challenges and now Los Alamos produces these radionuclides for sale through the National Isotope Development Center.
What sets Kozimor apart in isotope production and radiochemistry is his approach. Rather than simply developing a procedure, he focuses his work answering the question, “Why does a separation work?” In this way his team combines innovative separation techniques, fundamental inorganic chemistry, high-throughput robotics and X-ray spectroscopy to solve separation problems. Operating at the junction point of these four fields offers opportunity for identifying creative ways to remove unwanted contamination from valuable products such as cerium-134 or tellurium-119m/antimony-119. The results help researchers better understand how these elements behave, paving the way for safer and more effective separations relevant to nuclear chemistry communities’ needs.
LA-UR-26-28951
