Peter Debye Biography

Know this topic well? Help others and get FREE products!

World of Scientific Discovery on Peter Debye

Peter Debye is perhaps best known for his contribution to the theory of electrolytic dissociation, the Debye-Hückel theory, announced in 1923. Most of Peter Debye's professional work involved the application of physical laws to the structure and behavior of molecules. In the 1910s, he determined the dipole moments of many molecules, obtaining results that allowed him to calculate the polarity of such molecules. In recognition of this work, the unit of dipole moment, the debye, was named in his honor. Debye was awarded the 1936 Nobel Prize in chemistry for this research.

Petrus Josephus Wilhelmus Debije, was born on March 28, 1884 in Maastrict, the Netherlands to and Joannes Wilhelmus Debije, a foreman at a metalware manufacturer, and the former Maria Anna Barbara Ruemkens. He also had a younger sister. He is better known by the Anglicized form of his name, Peter Joseph William (or Wilhelm) Debye.

Debye attended the Hoogere Burger School in Maastricht from 1896 to 1901. He then enrolled at the Technische Hochschule in Aachen, across the Dutch-German border. Debye completed his studies at Aachen and received his degree in electrical engineering in 1905.

One of Debye's teachers at Aachen was the great German physicist Arnold Sommerfeld. When Sommerfeld was called to the chair of theoretical physics at the University of Münich in 1906, he asked Debye to join him as an assistant. Debye remained at Münich for five years, earning his doctorate in physics in 1908. The subject of his thesis was the effect of radiation on spherical particles with a variety of refractive properties. After earning his degree, Debye continued his research at Münich, serving as lecturer in physics during his last year there.

In 1911, Debye was offered the prestigious chair of theoretical physics at the University of Zürich, a post most recently held by Albert Einstein. During his year there, Debye studied the dipole moment of molecules, that is, its tendency to rotate in an external magnetic field, a property that is a function of the distribution of electric charge in (the polarity of) the molecule.

In 1912, Debye moved to the University of Utrecht, where he completed some exploratory research on the dipole of molecules. In 1914, Debye took a position at the University of Göttingen as professor of theoretical and experimental physics. His most important work at Göttingen involved X-ray diffraction studies. The use of X rays to determine the structure of materials had been developed only a few years earlier by Max Laue and by William Henry Bragg and William Lawrence Bragg. The most serious problem with the Laue-Bragg discoveries was that they required the preparation of relatively large crystals. Debye, working with a colleague named Paul Scherrer, found that X-ray diffraction could also be used with powders. They developed this technique and eventually reported on the structure of a number of materials examined by this method.

In 1920, Debye returned to the University of Zürich where he served as professor of experimental physics and director of the physics laboratory at the Federal Institute of Technology. During his stay at Zürich Debye developed the theory of electrolytic dissociation with his colleague, Erich Hückel. Pioneering work on the behavior of electrolytes, substances that conduct electricity through the movement of ions, had been conducted by the Swedish chemist Svante Arrhenius in the late 1880s. Arrhenius had argued that molecules break up spontaneously in solution, with the liberated ions becoming electrolytic agents.

Debye took a different approach to the problem by way of redefining the mathematical application to physicochemical data, instead of to each possible configuration of ions. Electrolytes must dissociate almost completely in solution, he proposed, because they are already completely ionic in the solid state. The reason they do not behave that way in solution, he said, is that each ion has become surrounded by other ions of opposite charge. The movement of ions through a solution, then, is disturbed by the dragging effect of the surrounding ions. Working with Hückel, Debye generated a mathematical theory that precisely described the behavior of electrolytes in solution.

In 1923, Debye also developed a theory that mathematically explained the Compton effect --the way the wavelengths of X rays change when they collide with electrons--and provided additional support for the wave-particle theory of electromagnetic radiation. He continued those studies when he moved to the University of Leipzig from 1927 to 1934 and then to the University of Berlin in 1934. Debye received the Nobel Prize in chemistry in 1936 in recognition of his contributions in many fields, including "his contributions to our knowledge of molecular structure through the investigations of dipole moments and on the diffraction of X rays and electrons in gases."

The rise of National Socialism resulted in an increase of political issues in German research, and Debye was soon required to become a German citizen in order to retain his post in Berlin. He chose instead to accept an appointment as professor of chemistry and head of the department at Cornell University in Ithaca, New York, in 1940. He became a U.S. citizen in 1946. Debye officially retired from his Cornell post in 1952, but continued his research in the field of polymer chemistry for another decade. During this time, Debye was much in demand as a lecturer, both in the United Sates and Europe and remained active in the scientific community until the age of 81. Debye's son Peter became a physicist and collaborated with his father on a number of occasions.

During his lifetime, Debye received many honors and awards, including Rumford Medal of the Royal Society (1930), the Lorentz Medal of the Royal Netherlands Academy of Sciences (1935), the Franklin Medal of the Franklin Institute (1937), the Faraday Medal (1949), the Gibbs Medal (1949), the Kendall Award (1957), the Nichols Medal (1963), and the Priestley Medal (1963) of the American Chemical Society.

Debye died of a heart attack, on November 2, 1966, at his home in Ithaca.