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Scientist Wins Award for High-Pressure Research
by Brookhaven National Laboratory
UPTON, NY — Yongjae Lee, a postdoctoral fellow in the Physics Department at the U.S. Department of Energy’s Brookhaven National Laboratory, has won the 2002 Alvin Van Valkenburg Award for his work on a newly discovered class of materials that expand under pressure. This award is given every second year in the name of renowned physicist Alvin Van Valkenburg, co-inventor of the diamond anvil cell, to honor a young scientist who uses this device in his or her scientific research. Lee was presented with a medal and gave a short talk on his work at a June 26, 2002, awards ceremony during the biannual Gordon Conference on “Research at High Pressure” in Meriden, New Hampshire, June 23 to 28.
“I am very honored to win this international young scientist award in high pressure sciences. Most of the discoveries and results would not have been possible without support and creative input from my many mentors and collaborators and the optimal instrumentation available at Brookhaven Lab,” said Lee, who dedicated the award to his newborn son, John J. Lee, and his wife, Heesung Kim.
The pressure-induced swelling of zeolites is the subject of Lee’s research. It was discovered by an international collaboration between Brookhaven Lab and the School of Chemical Sciences at England’s University of Birmingham. When subjected to great pressures in a diamond anvil cell, these zeolites expand as fluid from the surrounding medium is squeezed into their tiny pores. This unusual result may lead to applications for these materials as “molecular sponges” for soaking up chemical pollutants or even radioactive waste, because when the pressure is released and the material contracts, the fluid and possibly larger molecules or atoms could be trapped inside.
Using a technique called “powder diffraction” at Brookhaven’s National Synchrotron Light Source (NSLS), Lee and his collaborators were the first to decipher one such zeolite’s molecular structure last year. Their findings, published in the Journal of the American Chemical Society, explained, for the first time, the material’s unusual ability to absorb excess fluid, and showed where the extra liquid goes.
The experiments were done by subjecting the material to increasing pressure (from normal atmospheric pressure up to 50,000 times that pressure) in a diamond anvil cell. Essentially, the sample was squeezed between two diamonds, the world’s hardest substance, in a tiny chamber filled with water or another liquid to transmit the pressure evenly to all sides. The scientists then bombarded the sample with an intense beam of x-rays and analyzed how this beam was diffracted, or bent, as it bounced off the sample. Using computers, Lee then translated the diffraction pattern into a three-dimensional molecular structure.
As the pressure increased, the material at first appeared to compress, as one would expect. But as the pressure climbed between 0.8 and 1.5 gigapascals (8,000 to 15,000 times atmospheric pressure), the material expanded along two of its three dimensions. Analysis of the molecular structure revealed that, during the expansion, extra water molecules were squeezing into the zeolite’s pores, making it a “superhydrated” zeolite.
Lee came to Brookhaven Laboratory in 2001 as a postdoctoral fellow in the powder diffraction group, after completing his doctoral studies in geosciences at Stony Brook University. He had previously received a masters degree in geosciences from Stony Brook (1998) and a bachelors degree in earth system sciences from Yonsei University in Seoul, Korea (1996). Among other honors, Lee has been awarded a Certificate of Excellence from the Director of Brookhaven National Laboratory during 2002 NSLS Annual Users’ Meeting, a Sigma Xi Award for Excellence in Research at Stony Brook (2001), and the Pauling Prize at the 2000 American Crystallographic Association Meeting.
Lee’s research was funded by the U.S. Department of Energy, which supports basic research in a variety of scientific fields.
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