Since element 99 – einsteinium – was discovered in 1952 at the Lawrence Berkeley National Laboratory of the Department of Energy (Berkeley Lab) from the debris of the first hydrogen bomb, few experiments have been done by scientists because it is so difficult to create and especially radioactive. A team of Berkeley Lab chemists has overcome these obstacles to report the initial study identifying some of its properties, opening the door to a better understanding of the transuranic elements that are remnants of the actinide series.
Published in journal Nature, the study, “Structural and Spectroscopic Characterization of Einsteinium Compound,” was co-directed by Berkeley Lab scientist Rebecca Abergel and Los Alamos National Laboratory scientist Stosh Kozimor, and involved loaders -science from the two laboratories, UC Berkeley, and Georgetown University, several of which are graduate students and postgraduate associates. With less than 250 nanograms of the element, the team first measured the binding speed of einsteinium, a basic property of an element’s interaction with atoms and other molecules.
“There’s not a lot of information about einsteinium,” said Abergel, who heads the Element Berkeley Lab’s Heavy Chemistry group and is an assistant professor in UC Berkeley’s Nuclear Engineering department. “It was an amazing achievement to be able to work with this small amount of inorganic material and chemistry. It is important because the more we understand about its chemical behavior, the more we can apply this understanding to develop new materials or new technologies. , not just for einsteinium, but with the rest of the actinides as well. And we can establish trends in the quarterly schedule. “
Short-term and difficult to do
Abergel and her team used experimental facilities not available decades ago when einsteinium was first discovered – the Molecular Furnace at Berkeley Lab and the Stanford Synchrotron Radiation Lightsource (SSRL) at SLAC National Accelerator Laboratory, both load facilities DOE Science Office – to make a luminescence spectroscope. and X-ray spectroscopy tests.
But first, getting the sample in a usable format was almost half the battle. “This whole paper is a long series of unfortunate events,” she said cheerfully.
The material was manufactured at the High Flux Isotope Reactor at Oak Ridge National Laboratory, one of only a few places in the world capable of producing einsteinium, which involves spraying curium targets with neutrons to stimulate a long series of nuclear reactions. The first problem they encountered was that the sample was contaminated with a lot of californium, as it is very challenging to make pure einsteinium in a usable quantity.
So they had to scramble their original plan to use X-ray crystals – which are considered the gold standard for obtaining structural information on molecules that are highly radioactive but require a real sample. of metal – and instead came up with a new way to make samples and leverage specific research methods for elements. Researchers at Los Alamos provided vital support in this phase by designing a sample retainer that would be ideally suited for the challenges at the heart of einsteinium.
Then, tackling radioactive decay was another challenge. The Berkeley Lab team conducted their experiments with einsteinium-254, one of the most stable isotopes of the element. It has a half-life of 276 days, which is the time for half of the material to decompose. Although the team was able to perform many of the tests prior to the coronavirus pandemic, they had plans for follow-up tests that were disrupted as a result of a pandemic-related closure. By the time they were able to get back to their lab last summer, most of the sample was gone.
Band speed and beyond
However, the researchers were able to measure the binding speed with einsteinium and also found some physical chemistry behaviors that differed from what would be expected from the actinide series, which are elements of the lower layer of the quarterly schedule.
“Determining the bonding speed may not be interesting, but the first thing you would want to know is about how a metal binds to other molecules. What kind of chemical interactions a will this element have atoms and other molecules? ” Abergel said.
As soon as scientists get this picture of a molecular atomic arrangement that contains einsteinium, they can try to find interesting chemical properties and understand periodic motions. “By getting this piece of data, we get a better and broader understanding of how the whole actinide series behaves. And in that series, we have elements or isotopes that are useful for nuclear power generation or radiopharmaceuticals, “she said.
Interestingly, this research also provides an opportunity to examine what is outside the edge of the table from time to time, and perhaps discover a new element. “We are really starting to understand a little better what happens near the end of the record from time to time, and the next thing is, you could also see an einsteinium target to discover new elements, Abergel said. you could start looking for other elements and get closer to a (theoretical) stability island, “where nuclear physics has predicted that isotopes could have a half – life of minutes or even days, instead than the half-life half microsecond or less common in the superheavy elements.
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Study co-authors were Korey Carter, Katherine Shield, Kurt Smith, Leticia Arnedo-Sanchez, Tracy Mattox, Liane Moreau, and Corwin Booth of Berkeley Lab; Zachary Jones and Stosh Kozimor of Los Alamos National Laboratory; and Jennifer Wacker and Karah Knope of Georgetown University. The research was supported by the DOE Office of Science.
Founded in 1931 on the idea that teams better cope with the greatest scientific challenges, Lawrence Berkeley National Laboratory and their scientists have been recognized with 14 Nobel Prizes. Today, Berkeley Lab researchers develop sustainable energy and environment solutions, create useful new products, advance the boundaries of computing, and explore the mysteries of life, matter, and the universe. Scientists from around the world rely on the Lab’s facilities for their own discovery science. Berkeley Lab is a multi-platform national laboratory, managed by the University of California for the U.S. Department of Energy Science Office.
The DOE Office of Science is the single largest supporter of fundamental research in the physical sciences in the United States, and is working to address some of the most important challenges of our time. For more information, visit energy.gov/science.
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