Portal de Periódicos da CAPES

Harry George Drickamer (1918–2002): Electronic Phenomena in Condensed Matter at High Pressure

2003; Wiley; Volume: 42; Issue: 8 Linguagem: Inglês

10.1002/anie.200390227

1521-3773

F. Hensel,

High-pressure geophysics and materials

Over the past forty years, the application of high pressures has proven to be a powerful and nearly indispensable tool in chemistry, physics, geology, and biology research. Ever-increasing sophistication in experimental high-pressure techniques coupled with new theoretical developments have resulted in important advances in the understanding of the molecular structures, electronic properties, dynamics, and reactivity of condensed matter. One of the towering pioneers of this development was Harry G. Drickamer (Figure 1), Professor of Chemical Engineering, Chemistry and Physics at the University of Illinois in Urbana-Champaign, who died of a stroke on May 6, 2002 in Urbana, Illinois, at the age of 83. Harry G. Drickamer (Copyright Dept. Chemical Engineering, University of Illinois, Urbana, IL, USA). Harry Drickamer was born on November 19, 1918 in Cleveland, Ohio. After graduating from high school he attended Indiana University for a short period. He then transferred to the University of Michigan, where he received his bachelor's degree in 1941, his master's degree in chemical engineering in 1942, and his doctorate in chemical engineering in 1946. That same year he joined the University of Illinois in Urbana-Champaign, where he was appointed, in recognition of the breadth of his research, Center of Advanced Study Professor of Chemical Engineering, Chemistry, and Physics, the highest accolade bestowed by the University on its faculty members. During his more than 50 years of research in Urbana, he developed the concept that pressure can change the chemical and physical properties of condensed matter by its effect on the electronic orbitals, a method he called “Pressure Tuning Spectroscopy”. Exploitation of this method led to his discovery in the late 1950s of a wide variety of electronic transitions in solids, including insulator–metal transitions for six elements and more than 30 covalent and ionic compounds, metal–semiconductor transitions for the elements calcium, strontium, and ytterbium, (which are metals at one atmosphere and which become semiconductors at high pressure), and s–d or 4f–5d transitions of the conducting electrons in alkali and rare-earth metals, respectively. In the 1970s he also investigated closely related pressure-induced changes to magnetic properties, such as high-spin–low-spin transitions and paramagnetic–ferromagnetic transitions in ferrous compounds and in iron. Furthermore, he discovered electronic transitions with chemical consequences, such as the stabilization of reactive charge-transfer states of electron donor–acceptor complexes at high pressures and the pressure-induced conversion of photochromic into thermochromic materials. In the 1980s his research expanded to high-pressure investigations in protein chemistry, organic photochemistry, and the efficiency of luminescence devices. Harry Drickamer's style of experimental research kept him in close contact with theoretical work. In this way, he was able to provide clear-cut and unequivocal tests for a large number of theories, including the ligand-field theory, van Vleck's theory of spin-flip transitions, Mulliken's theory of bonding in electron donor–acceptor complexes, the Förster–Dexter theory of energy transfer in phosphors, and van Vleck's theory of high-spin–low-spin transitions. He also developed successful tests for theories on the efficiency of phosphor and laser materials, including II-VI and III-V compounds with zinc-blende structure, rare-earth oxides, chelates, and organic phosphors. The list of his awards and honors is too long to relate in full, and reflects not only universal respect and admiration for his scientific research, but also the remarkable breadth of his activities. The 27 awards he received were for both research and teaching, and were from organizations in physics, chemistry, and chemical engineering. Among them were the Oliver E. Buckley Prize in Condensed Matter Physics from the American Physical Society (1967), the Irving Langmuir Award in Chemical Physics (1974), the Peter Debeye Award of the American Chemical Society (1987), the first P. W. Bridgman Award of the International Association for the Advancement of High-Pressure Science and Technology (1977), and a Research Award from the Alexander von Humboldt Foundation of the Federal Republic of Germany (1986). In 1989, President George H. W. Bush awarded him the National Medal of Science. Drickamer's laboratory in Urbana attracted scientists and students from many places around the world. His passionate interest in high-pressure research continued after his retirement in 1989. Even then, he did not change his research schedule, but continued to maintain an active and successful research group and was in the laboratory six days a week. The results of 56 years of high-pressure research were published in more than 450 original contributions to the scientific literature. A summary, in Drickamer's own words, of the impact of “Pressure Tuning Spectroscopy”, can be found in Annual Reviews Materials Science 1990, 1–17. Insight into his research can be found in his review on “Electronic Transitions in Transition Metal Compounds at High Pressure” (Angew. Chem. 1974, 86, 61–79; Angew. Chem. Int. Ed. Engl. 1974, 13, 39–47). Dickamer's scientific work has affected high-pressure research in an important way and will continue to do so in the future. Those who have been fortunate and privileged enough to work with him as students, colleagues, or friends owe him a great debt of gratitude. We will miss him.