Karel Frederik Niessen (1895 in Velsen – 1967) was a Dutch theoretical physicist who made contributions to quantum mechanics and is known for the Pauli–Niessen model.

Education

Niessen began his studies in physics at the University of Utrecht in 1914. In 1922, he received his doctorate under L. S. Ornstein. He was an assistant at the University from 1921 to 1928, except for his postdoctoral study and research at the Ludwig Maximilian University of Munich under Arnold Sommerfeld, 1925 to 1926 on a Rockefeller Foundation Fellowship. He also spent 1928 to 1929 on a Rockefeller Foundation Fellowship at the University of Wisconsin–Madison. In 1922, Niessen’s doctoral thesis, as well as Wolfgang Pauli’s extended doctoral thesis, dealt with the hydrogen molecule ion in the Bohr–Sommerfeld framework. Their work is referred to as the Pauli-Niessen model. Their works helped to show the inadequacy of the old quantum mechanics, which gave physicists the impetus to explore new paths which led to the matrix mechanics formulation of quantum mechanics by Werner Heisenberg and Max Born in 1925 and the wave mechanics formulation by Erwin Schrödinger in 1926, which were shown to be equivalent.

Career

Upon Niessen’s return to the Netherlands in 1929, he took a lifelong position as a theoretical physicist at Philips Electronics in Eindhoven.

Selected Literature