Peter Debye
Peter Joseph William Debye was born on the 24th of March 1884 in Maastricht, Netherlands. He enrolled at Aachen University of Technology in 1901 to study electrical engineering. By 1905 he had completed his first degree and published a mathematically elegant paper on eddy currents in 1907. Arnold Sommerfeld became his professor and later claimed that Debye was his most important discovery. Sommerfeld moved to Munich in 1906 and took Debye with him as an assistant. Debye earned his Ph.D. dissertation on radiation pressure in 1908. In 1910 he derived Planck's radiation formula using a method Max Planck agreed was simpler than his own. Albert Einstein took a professorship at Prague in 1911 while Debye held his old chair at Zurich. The following year Debye moved to Utrecht where Cornelis Wind had died in 1911. He then went to Göttingen in 1913 before returning to ETH Zurich in 1920. His career path continued to Leipzig in 1927 and finally Berlin in 1934.
Debye applied the concept of dipole moment to asymmetric molecules in 1912. This work developed equations relating dipole moments to temperature and dielectric constant. Units of molecular dipole moments are now termed debyes in his honor. That same year he extended Einstein's theory of specific heat to lower temperatures by including contributions from low-frequency phonons. In 1913 he introduced elliptical orbits into Niels Bohr's atomic structure theory. Paul Scherrer collaborated with Debye between 1914 and 1915 on calculating temperature effects on X-ray diffraction patterns. Their joint work became known as the Debye-Waller factor. Erich Hückel worked alongside him in 1923 to improve Svante Arrhenius' theory of electrical conductivity. Although Lars Onsager improved their equation in 1926, the Debye-Hückel theory remains a major step forward. Debye also developed a theory explaining the Compton effect regarding frequency shifts when X-rays interact with electrons. Later work at Cornell involved light-scattering techniques derived from earlier X-ray scattering research. These methods determined the size and molecular weight of polymer molecules during World War II.
The Nobel Committee awarded Peter Debye the Chemistry prize in 1936 for contributions to molecular structure studies. His primary focus was work on dipole moments and X-ray diffraction. He received the Lorentz Medal in 1935 before winning the Nobel. The Rumford Medal followed in 1930 for specific heats and X-ray spectroscopy. The Franklin Institute honored him with the Franklin Medal in 1937. In 1947 he was elected to the United States National Academy of Sciences. The Priestley Medal came his way in 1963. The National Science Foundation presented him with the National Medal of Science in 1965. Alpha Chi Sigma inducted him into its Hall of Fame in 1982. He became an International Honorary Member of the American Academy of Arts and Sciences in 1927. Einstein himself voted for Debye's Max Planck medal nomination in 1950 despite their political differences.
Debye traveled to the United States in May 1939 to deliver the Baker Lectures at Cornell University. He left Germany in early 1940 after accepting a professorship there. He arrived in New York in early February 1940 following a ship departure from Genoa in January. His wife Mathilde reached the US by December 1940 while his daughter remained behind in Berlin. Debye became an American citizen in 1946 after crossing the border into Canada and returning on an immigration visa. He chaired the chemistry department at Cornell for ten years before retiring in 1952. Unlike his European phase where he moved cities every few years, he stayed at Cornell until death. He continued research until suffering a fatal heart attack in November 1966. His son Peter P. Debye had already been in the US before his father departed. The younger Debye collaborated with him on some research projects during this period.
A book titled Einstein in the Netherlands appeared in January 2006 written by Sybe Rispens. It claimed Debye actively cleansed German science institutions of Jewish elements as chairman of the Deutsche Physikalische Gesellschaft. On the 9th of December 1938 Debye wrote to DPG members stating membership by German Jews could not continue under Nuremberg laws. He signed the letter with Heil Hitler despite later allegations of Nazi collaboration. An investigation by Cornell University released a report on the 31st of May 2006 finding no evidence supporting accusations that Debye was a Nazi sympathizer. The NIOD report from 2007 described Rispens's presentation as a caricature of opportunism. The Terlouw Commission advised universities in January 2008 to keep using Debye's name for institutes. They concluded he was not an anti-semite or collaborator but also not a resistance hero. Max von Laue approved the controversial letter while other societies followed Debye's lead. Albert Einstein and Lise Meitner knew Debye intimately yet never protested his receiving the Max Planck medal.
Debye shielding describes how fixed electric charges are shielded by redistributing mobile particles in plasmas. The Debye length measures typical distance required for full shielding in plasma environments. His model explains heat capacity of solids as a function of temperature. Scientists use the debye unit for measuring electric dipole moments today. Crystalline lattices exhibit characteristic vibrational frequencies called Debye frequency. Dielectric relaxation responses follow patterns known as Debye relaxation. The Debye-Hückel equation calculates activity coefficients in electrolyte solutions. Researchers apply the Debye-Scherrer method for X-ray powder diffraction analysis. A lunar crater named Debye sits on the far northern hemisphere of the moon. Minor planet 30852 Debye bears his name alongside the Lorenz-Mie-Debye theory. Maastricht University maintains the Peter Debye Prize for scientific research despite earlier reconsiderations. The City of Maastricht declared no reason to change names of Debye Street or Debye Square. His monument stands in the square that bears his name created by Felix van de Beek in 1998.
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Common questions
When was Peter Debye born and where did he grow up?
Peter Joseph William Debye was born on the 24th of March 1884 in Maastricht, Netherlands. He enrolled at Aachen University of Technology in 1901 to study electrical engineering.
What major scientific theories did Peter Debye develop during his career?
Peter Debye applied the concept of dipole moment to asymmetric molecules in 1912 and derived Planck's radiation formula using a method Max Planck agreed was simpler than his own. His work also included extending Einstein's theory of specific heat to lower temperatures by including contributions from low-frequency phonons.
Why did Peter Debye move to the United States in 1939?
Peter Debye traveled to the United States in May 1939 to deliver the Baker Lectures at Cornell University before leaving Germany in early 1940 after accepting a professorship there. He arrived in New York in early February 1940 following a ship departure from Genoa in January.
Did Peter Debye collaborate with Nazi institutions or support anti-Semitic policies?
On the 9th of December 1938 Debye wrote to DPG members stating membership by German Jews could not continue under Nuremberg laws and signed the letter with Heil Hitler despite later allegations of Nazi collaboration. An investigation by Cornell University released a report on the 31st of May 2006 finding no evidence supporting accusations that Debye was a Nazi sympathizer.
What awards and honors did Peter Debye receive for his scientific contributions?
The Nobel Committee awarded Peter Debye the Chemistry prize in 1936 for contributions to molecular structure studies while he received the Lorentz Medal in 1935 before winning the Nobel. The Franklin Institute honored him with the Franklin Medal in 1937 and the National Science Foundation presented him with the National Medal of Science in 1965.