John William Nicholson

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John William Nicholson , FRS (born November 1, 1881 in Darlington , † October 3, 1955 in Oxford ) was a British mathematician and physicist.

Nicholson studied at Middlesbrough High School and the University of Manchester. In 1904 he completed the Tripos exams at Cambridge University , where he received several awards (Isaac Newton Scholar Prize 1906, Smith Prize 1907, Adams Prize 1913 and 1917). He was a lecturer at the Cavendish Laboratory in Cambridge and then at Queen's University in Belfast. In 1912 he became a mathematics professor at King's College London. From 1921 until his retirement in 1930 he was a Fellow and Director of Studies at Balliol College, Oxford.

In 1911 he proposed - independently of Ernest Rutherford and others - a model of the atom similar to the planetary system, with the atomic nucleus in the center. His model also had elements of the atomic model by JJ Thomson , in which the positive charge was distributed over the atom and the electrons were distributed in it. The atoms were determined by the positive charge in the nucleus, regardless of the number and total charge of their electrons (in this respect, he also anticipated the order of the periodic table according to the nuclear charge instead of atomic weight). The hydrogen atom, in his opinion, was not stable and would collapse and the smallest atom would consist of two electrons around the nucleus. In the case of stable atoms, two or more electrons would keep themselves in check by repulsion and would be distributed equidistantly (for example two electrons in a ring). After him there was also a series of four proto-atoms or proto-elements, from which the elements on earth had been formed and which only existed in space in stellar nebulae and around stars. The proto-elements were "hydrogen" (but with nuclear charge 3, atomic weight 1.008), coronium (charge 2, atomic weight 0.51282), protofluorinum (charge 5, atomic weight 2.361) and nebulium (charge 4, atomic weight 1.6281) called. In Nebulium, for example, four electrons revolved around the nucleus. He tried to explain the atomic weights of the elements and spectra of galactic nebulae .

In 1927 Ira Sprague Bowen succeeded in assigning the observed spectral lines of the nebulium to the forbidden transition of the doubly ionized oxygen . The coronium is the green emission line of the 13-fold positively charged Fe 13+ ion, [Fe XIV] at 530.3 nm.

After Eric Scerra, he was the first to propose the quantization of angular momentum (in units of the reduced Planck constant), in this case of electrons in atoms. This probably also influenced Niels Bohr in the development of his own model. Bohr considered Nicholson's theory to be pretty insane on the one hand , but also used it as a model from which he set himself apart with his own theory.

Nicholson became a Fellow of the Royal Society in 1917. He was also a Fellow of the Royal Astronomical Society , Vice President of the London Physical Society and President of the Roentgen Society.

literature

  • Eric Scerri: A tale of seven scientists, Oxford UP 2016

Individual evidence

  1. ^ A b W. Wilson: John William Nicholson. 1881-1955 . In: Biographical Memoirs of Fellows of the Royal Society . tape 2 , January 11, 1956, p. 209-214 , doi : 10.1098 / rsbm.1956.0014 .
  2. ^ IS Bowen: The Origin of the Nebulium Spectrum (Letters to Editor) . In: Nature . tape 120 , no. 3022 , 1927, pp. 473 , doi : 10.1038 / 120473a0 .
  3. ↑ Scerri, A tale of seven scientists, 2016, p. 34
personal data
SURNAME Nicholson, John William
BRIEF DESCRIPTION British mathematician
DATE OF BIRTH November 1, 1881
PLACE OF BIRTH Darlington
DATE OF DEATH 3rd October 1955
Place of death Oxford