Arizona State University Regents Professor Austen Angell, of the School of Molecular Sciences, recently enjoyed three days of festivities at Chalmers University in Gothenburg, Sweden to receive the 2019 Lise Meitner Award.
The Gothenburg Lise Meitner Award is presented every year to a scientist who has made a breakthrough discovery in physics. In conjunction with the award ceremony, the laureate gives a lecture in honor and memory of the female nuclear physicist who many now agree was deserving of a Nobel Prize for her breakthrough insight into the mechanism of nuclear fission. She was unfairly denied because of her sex and religious affiliation.
The last American Meitner awardee was Mildred Dresselhaus, a physics professor emeritus from MIT, in 2013, who also received the 2012 Enrico Fermi Award and the U.S. Presidential Medal of Freedom in 2014.
“When I read of the accomplishments of previous awardees, I was very humbled and also a little nervous,” Angell said. The citation this year reads, “For inventing the concept of fragility of glass-forming liquids”.
The liquid state of matter is central to many of nature’s cycles, and certainly to life itself, but is poorly understood because of its lack of order.
“Glass-forming liquids range from volcanic to cryogenic and have fluidities that can be measured over 17 orders of magnitude, so are still less understood," Angell said.
“Fragility” captures, in one word and one diagram, all the variations in the fluidity that are found in any of nature’s liquids, and hints at some universality in character that theoreticians find tantalizing, while still out of reach.
The formal award is followed by a symposium in which other subjects of interest to the Gothenburg Physics Center are explored. The final day includes a visit to the peaceful nearby town of Kungalv, where Meitner spent the Christmas of 1938 after flight from Germany, and where she discovered her insight into the explanation of physicist Otto Hahn’s experimental data.
This year the emphasis in the symposium was on ionic liquids as electrolytes and battery components. One of the speakers was Angell’s son, Michael, who works with Hongjie Dai at Stanford University on aluminum-graphite batteries.
Angell has more than 500 publications and a Google Scholar H index of 109, and his work has been recognized with a number of awards, including the Hildebrand award of the American Chemical Society, the Turnbull lecture award of the Materials Research Society, the American Electrochemical Society’s Bredig Award and the Morey Award from the American Ceramic Society.
Video by Chalmers University, Gothenburg, Sweden
During his long career, Angell has worked mostly on liquids and glasses, but he has also published on geochemical, biophysical and battery electrolyte problems. He is currently making a major effort in the energy storage and conversion disciplines.
Angell has had collaborations with researchers at Chalmers for nearly 50 years, and he has been a faculty opponent on several occasions. He was nominated for the Gothenburg Lise Meitner Award by professors Patrik Johansson and Aleksandar Matic, both at the Department of Physics at Chalmers University.
“Scandinavia, in general, and Sweden and Chalmers in particular, have a long history in the field of molten salt and ionic liquid chemistry that I entered before I ever knew I would become an academic,” Angell said.
What does Angell hope to achieve with his research?
“This is not an easy question to deal with, without sounding trivial or pompous," he said. "One obvious answer is that I wish to quickly solve the problems that I have proposed to my funding agencies, so that they will continue to support my research. The more serious answer is that I wish to earn the respect and friendship of my many colleagues in the international quest for new solutions to recognized scientific problems, especially those of societal importance."
Lise Meitner and nuclear fission
This year, 80 years have passed since the Austrian-Swedish physicist Lise Meitner and her nephew Otto Frisch provided a physical explanation for the occurrence of nuclear fission. Her long-term collaborator Otto Hahn was the only one to be awarded the Nobel Prize (surprisingly in chemistry) in 1944 for the discovery of the fission of heavy nuclei.
Nuclear fission, the physical process by which very large atoms like uranium split into pairs of smaller atoms, is what makes nuclear bombs and nuclear power plants possible. But for many years, physicists believed it energetically impossible for atoms as large as uranium (atomic mass = 235 or 238) to be split into two.
That all changed on Feb. 11, 1939, with a letter in Nature that described exactly how such a thing could occur and even named it fission. In that letter, Meitner, with the assistance of her young nephew Frisch, provided a physical explanation of how nuclear fission could happen.
It was a massive leap forward in nuclear physics, but Meitner was excluded from the victory celebration because she was a Jewish woman.
What happens when you split an atom
Meitner based her fission argument on the “liquid droplet model” of nuclear structure — a model that likened the forces that hold the atomic nucleus together to the surface tension that gives a water droplet its structure.
She noted that the surface tension of an atomic nucleus weakens as the charge of the nucleus increases, and could even approach zero tension if the nuclear charge was very high, as is the case for uranium (charge = 92+). The lack of sufficient nuclear surface tension would then allow the nucleus to split into two fragments when struck by a neutron — a chargeless subatomic particle — with each fragment carrying away very high levels of kinetic energy. Meisner remarked: “The whole ‘fission’ process can thus be described in an essentially classical (physics) way.”
Meitner went further to explain how her scientific colleagues had gotten it wrong. When scientists bombarded uranium with neutrons, they believed the uranium nucleus, rather than splitting, captured some neutrons. These captured neutrons were then converted into positively charged protons and thus transformed the uranium into the incrementally larger elements on the periodic table of elements — the so-called “transuranium”, or beyond uranium, elements.
Some people were skeptical that neutron bombardment could produce transuranium elements, including Irene Joliot-Curie, Marie Curie’s daughter. Joliot-Curie had found that one of these new alleged transuranium elements actually behaved chemically just like radium, the element her mother had discovered. Joliot-Curie suggested that it might be just radium (atomic mass = 226) an element somewhat smaller than uranium that was coming from the neutron-bombarded uranium.
Meitner had an alternative explanation. She thought that, rather than radium, the element in question might actually be barium, an element with a chemistry very similar to radium. The issue of radium versus barium was very important to Meitner because barium (atomic mass = 139) was a possible fission product according to her split uranium theory, but radium was not as it was too big.
Hahn found that Meitner was correct: The element in the sample was indeed barium, not radium. Hahn’s finding suggested that the uranium nucleus had split into pieces — becoming two different elements with smaller nuclei — just as Meitner had suspected.
Meitner should have been the hero of the day, and the physicists and chemists should have jointly published their findings and waited to receive the world’s accolades for their discovery of nuclear fission. But unfortunately, that’s not what happened.
“Through the years, I have always known the name of Lise Meitner in connection with the early days of radioactivity discovery. But I didn’t know the details of her struggles with prejudice, not to say persecution,” Angell said. “I think it is great that the Gothenburg Physics Center has undertaken to play a role in keeping her name alive in our thoughts, given its proximity to her work-site.”
More Science and technology
Advances in forensic science improve accuracy of ‘time of death’ estimates
Accurate “time of death” estimates are a mainstay of murder mysteries and forensic programs, but such calculations in the real…
Unpacking a plastic paradox
Demand for plastics exists in a constant paradox: thin yet strong, cheap yet sophisticated, durable yet degradable. The various…
New chief operations officer to help ramp up SWAP Hub advancements
Last September, the Southwest Advanced Prototyping Hub — a collaboration of more than 130 industry partners led by Arizona State…