Arnold Sommerfeld called Peter Debye his greatest discovery
Arnold Sommerfeld spotted a young electrical engineering student from Maastricht at Aachen and later said finding him was his most important achievement. Peter Debye went on to derive Planck's radiation law more simply than Planck himself, lend his name to the unit of molecular polarity, and win a Nobel Prize in Chemistry.
Born in Maastricht on 24 March 1884, Debye finished an electrical engineering degree at Aachen in 1905 and then followed Sommerfeld to Munich as his assistant, earning a doctorate on radiation pressure in 1908. Two years later his derivation of the Planck formula won Planck's own agreement that it was simpler. He married Mathilde Alberer, daughter of the keeper of his boarding house, in 1913.
His career zigzagged across Europe. He took over Einstein's former chair in Zurich in 1911, then moved to Utrecht, Göttingen, ETH Zurich and Leipzig, and in 1934 succeeded Einstein again as director of the Kaiser Wilhelm Institute for Physics in Berlin. In 1912 alone he applied dipole moments to lopsided molecules, which is why dipole moments are measured in debyes, and stretched Einstein's theory of specific heat to low temperatures. With Erich Hückel in 1923 he refined the theory of how salt solutions conduct electricity, and that year he also explained the Compton effect.
His Berlin years remain disputed. As chairman of the German Physical Society in December 1938 he signed a letter asking Jewish members covered by the Nuremberg laws to resign, and a 2006 book by Sybe Rispens argued he helped purge science institutions. Defenders note that the anti-Nazi Max von Laue approved the letter, that Debye and Dutch colleagues helped Lise Meitner escape across the border, and that Einstein himself voted for Debye's Max Planck Medal in 1950. Even so, Utrecht decided to rename its Debye institute, and Maastricht University reconsidered its Debye prize.
Debye sailed from Genoa in January 1940 and joined Cornell that June, chairing chemistry for ten years and becoming a citizen in 1946. After roaming cities in Europe, he stayed put in Ithaca, using light scattering to measure polymers, a line of work that began with wartime synthetic rubber. A trout fisherman, cactus collector and cigar lover, he died after a second heart attack in November 1966.
Source: Peter Debye
