Nuclear chemist Darleane C. Hoffman, Ph.D., of the University of California at Berkeley and the E. O. Lawrence Berkeley National Laboratory (LBNL), will receive the Priestley Medal, the highest honor of the American Chemical Society, the world's largest scientific society. The award is named for Joseph Priestley, who reported the discovery of oxygen in 1774. It will be presented to Hoffman on March 28 at the Society's 219th national meeting in San Francisco.
Hoffman is the second woman to receive the award since it was established in 1923. Past winners include Nobel Laureate Glenn Seaborg, leader of the group that discovered plutonium; Linus Pauling, who was awarded a Nobel Prize for his work on chemical bonding and molecular structure; and Carl Djerassi, inventor of the birth control pill.
Honored for her contributions to research and education in nuclear and radiochemistry, Hoffman is internationally renowned for her pioneering research on transactinide elements - those that decay in minutes or even seconds. She discovered evidence for primordial plutonium in nature in the form of the very long-lived species plutonium-244. In 1993 her group verified the existence of seaborgium, a rare element named after Glenn Seaborg.
In 1971, Hoffman and her colleagues at Los Alamos National Laboratory reported that spontaneous fission, a process in which the atom of a nucleus splits on its own and releases energy, can result in two nearly equal, stable parts. This phenomenon, called symmetrical mass division, "was Š not expected - and not really predictable," Hoffman recounts. "It's one of the processes that will determine how many new elements can actually exist."
Most recently, Hoffman's group at Berkeley has pioneered the use of a technique called "one-atom-at-a-time" chemistry: Researchers determine the chemical properties of short-lived elements by measuring the rate of radioactive decay of individual atoms, combine the results, and compare these properties to other known elements. "One of the most fundamental studies in all of chemistry is the determination of the chemical properties of the elements in the periodic table," Hoffman notes.
Even after nearly 50 years in the field, Hoffman is still active in research. "One of the reasons why I don't really want to retire [is that] it's a really exciting time for both the nuclear and the chemical aspects of nuclear chemistry," she says.
Hoffman also enjoyed teaching nuclear chemistry to undergraduates. "The more people you can teach about these things, the better educated the general public will be and the better they will know how to deal with some of the problems and benefits" associated with nuclear energy and waste, she explains.
While Hoffman was an undergraduate at Iowa State University, her interest in chemistry was sparked by "a wonderful woman professor named Nellie Naylor." She taught a course in chemistry for home economics, which was required for Hoffman's intended (and later abandoned) major in applied art. A subsequent research assistantship introduced her to nuclear chemistry in 1947. "We had a 68 MeV (million electron volt) synchrotron that was just being finished there, and so we could go and do experiments and find new isotopes. You had the thrill because you were seeing something that nobody -- at least, no human -- had ever seen before. It was a great time," she recalls.
Hoffman graduated from Iowa State University with a B.S. in chemistry in 1948 and received her Ph.D. there in 1951. Her first professional position was at Oak Ridge National Laboratory, followed by 31 years at Los Alamos, where she had the opportunity to take a sabbatical year (1978-79) as a Guggenheim Fellow with Glenn Seaborg's group in Berkeley. After returning to Los Alamos in 1979 she served as division leader of the Chemistry-Nuclear Chemistry and Isotope and Nuclear Chemistry divisions. She went back to Berkeley in 1984 to become professor of chemistry at the University of California, Berkeley, and faculty senior scientist and leader of the Heavy Element Nuclear and Radiochemistry Group at LBNL.
Today, Hoffman is professor of the graduate school in the department of chemistry at the University of California, Berkeley, and co-leader of the Heavy Element Nuclear and Radiochemistry Group at LBNL. She was charter director (1991-96) of the Seaborg Institute for Transactinium Science, located at Lawrence Livermore National Laboratory, Livermore, Calif. Hoffman received the U.S. National Medal of Science in 1997, the Francis P. Garvan-John M. Olin Medal from ACS in 1990, and the ACS Award in Nuclear Chemistry in 1983. The author of more than 200 research papers, Hoffman chaired the National Research Council's Committee on Nuclear and Radiochemistry and served on the National Research Council's Board of Radioactive Waste Management.
Dr. Hoffman will deliver the Priestley Medal address at a dinner honoring this year's ACS award recipients on Tuesday, March 28, at 7:30 p.m., at the Hilton. Reporters covering this event must first contact the ACS Press Office at 415-923-7510.
A nonprofit organization with a membership of 161,000 chemists and chemical engineers, the American Chemical Society www.acs.org publishes scientific journals and databases, convenes major research conferences, and provides educational, science policy and career programs in chemistry. Its main offices are in Washington, D.C., and Columbus, Ohio.