Peter Joseph William Debye ForMemRS was born on this date in 1884. He was a Dutch-American physicist and physical chemist, and 1936 Nobel laureate in Chemistry. His first major scientific contribution was the application of the concept of dipole moment to the charge distribution in asymmetric molecules in 1912, developing equations relating dipole moments to temperature and dielectric constant. In consequence, the units of molecular dipole moments are termed debyes in his honour. Also in 1912, he extended Albert Einstein’s theory of specific heat to lower temperatures by including contributions from low-frequency phonons. See Debye model. In 1913, he extended Niels Bohr’s theory of atomic structure, introducing elliptical orbits, a concept also introduced by Arnold Sommerfeld. During 1914–1915, Debye calculated the effect of temperature on X-ray diffraction patterns of crystalline solids with Paul Scherrer (the “Debye–Waller factor”). In 1923, together with his assistant Erich Hückel, he developed an improvement of Svante Arrhenius’ theory of electrical conductivity in electrolyte solutions. Although an improvement was made to the Debye–Hückel equation in 1926 by Lars Onsager, the theory is still regarded as a major forward step in our understanding of electrolytic solutions. Also in 1923, Debye developed a theory to explain the Compton effect, the shifting of the frequency of X-rays when they interact with electrons.
Adolf Friedrich Johann Butenandt was born on this date in 1903. He was a German biochemist. He was awarded the 1939 Nobel Prize in Chemistry for his “work on sex hormones.” He initially rejected the award in accordance with government policy but accepted it in 1949 after World War II.
Sir John Cowdery Kendrew, CBE, FRS was born on this date in 1917. He was an English biochemist and crystallographer who shared the 1962 Nobel Prize in Chemistry with Max Perutz; their group in the Cavendish Laboratory investigated the structure of heme-containing proteins.