Darleane Christian Hoffman, PhD, is an American nuclear chemist (b. 1926) who is currently Faculty Sr. Scientist, Nuclear Science Division, Lawrence Berkeley National Laboratory and Professor Emerita, Chemistry Department, UC Berkeley.
Early in her career, she spear-headed isolation of minute quantities of a very long-lived form of plutonium (lifetime of more than 83 million years and mass 244) from Precambrian bastnasite. This was the first confirmation of its present existence on planet Earth; the results and their implications were published in Nature magazine in 1971 bringing her considerable recognition.
Darleane is also well known for leading the team of researchers that confirmed discovery of the chemical element 106 in 1974, thus allowing the discovery team to propose naming it “Seaborgium” after Glenn T. Seaborg, Chairman of the U. S. Atomic Energy Commission from 1961-1971. The name was finally officially approved in 1979 while Seaborg was still alive.
During her long career, she pioneered “one atom-at-a-time” techniques, using both manual and computer-controlled systems to characterize some of the most elusive forms of matter—the very heaviest chemical elements. These are difficult to produce and exist for only minutes or seconds and must be studied at the accelerators where they are produced, e.g., at cyclotrons or other suitable accelerators in Berkeley, CA, Dubna, Russia or the Institute for Heavy Element Research in Germany, and more recently in Japan. Many of these elements decay via fission or spontaneous fission in which the element is essentially destroyed making positive identification especially difficult. Hoffman has made important discoveries about the nature of the fission process and has gained fundamental knowledge about the nature of fission, the atomic process at the heart of nuclear power.
Hoffman grew up in small towns in Iowa. Her father was a school superintendent and often taught mathematics, a subject which she also enjoyed. After high school she entered Iowa State College (now Iowa State University, Ames, Iowa) as an applied art major although she considered mathematics. She soon changed to chemistry because of the inspiring teaching of her freshman Chemistry teacher Dr. Nellie Naylor (a spinster) who taught not only the fundamentals, but discussed new developments, environmental applications, and the discovery of radium by Marie Curie. After graduation Hoffman decided to stay at Iowa State to earn her Ph.D. Her father urged her to get a teaching certificate as well so she would be assured of a job when she finished. Darleane replied that she would never ever teach as in those days if a woman teacher married, she had to resign her position!! She vowed to follow the model of Marie Curie and do research and marry if she chose to, and have children if she chose to! When she told her female advisor (also a spinster) of her decision she asked Darleane if she thought chemistry was a suitable profession for a woman!
Darleane met Marvin Hoffman when he began graduate study in Physics at Iowa State in 1948. They became well acquainted because they conducted research together at the newly built Synchrotron there. Darleane vowed she would never marry until after she completed her Ph. D. which she did in December 1951 and they married on Dec. 26. In Jan. 1952 she accepted a position at Oak Ridge National Laboratory in Tennessee, while Marvin remained in Iowa to finish his Ph.D. She found out many years later that Marvin’s research advisor told him he had made a horrible mistake—he should have married “some sweet young thing who would stay home and take care of you!” That didn’t sound like Darleane!
After Marvin received his Ph. D. in 1952 he decided to return to the Nuclear Test Division of the Los Alamos Scientific Laboratory Division where he had been as a summer student. Darleane resigned from ORNL to follow him to Los Alamos in January 1953. She finally managed to find the position in the Radiochemistry Group that Marvin had been assured she would have. In their innocence they had nothing in writing! Darleane was not able to ‘collect’ her position until March of 1953 after being told by the Personnel Dept. that they didn’t hire women in that Division (not true) and then having her Q-clearance lost between Oak Ridge and Los Alamos! Incredible!
While at Los Alamos Hoffman led studies at the Nevada Test Site to investigate migration of radioactivity from the site of underground nuclear weapons tests and to find a suitable underground storage site for nuclear waste products.
The Hoffmans remained at Los Alamos from 1953 until 1984 except for sabbaticals in Norway (1964) and Berkeley (1997) with Prof. Seaborg’s group. Darleane left in 1984 to become tenured professor at the University of California, Berkeley, and Heavy Element Group Leader at Lawrence Berkeley National Laboratory, as successor to Glenn Seaborg who was retiring, and became a wonderful mentor and colleague.
Honors include: 1997 National Medal of Science; 2000 Am. Chem. Soc. Priestley Medal; Hevesy Medal Award 2011, and numerous other honors. In addition to having a long, productive career, she has also managed to have a full family life, with two grown children and three grandchildren.