Kai Siegbahn (1918–2007) was awarded the Nobel Prize in Physics 1981 ”for his contribution to the development of high-resolution electron spectroscopy”.
Kai Siegbahn studied physics, maths and chemistry at Uppsala University from 1936 to 1942 and later got his degree in Stockholm 1944. After having worked as a researcher at the Nobel Institute for Physics 1942–51 he became Professor of Physics at the Royal Institute of Technology 1951–1954 and Professor of Physics at Uppsala University 1954–1984.
Siegbahn conducted research within nuclear physics, electron optics, plasma physics, and atomic and molecular physics. He developed very exact methods for analysing the energy in electrons emitted from radioactive materials or from atoms and molecules when they are excited by X-rays. The development of this so called electron spectroscopy with very high resolution led to, among other things, the discovery that the energy levels of electrons depends on the atom’s chemical surroundings. This has led to the often used Electron Spectroscopy for Chemical Analysis, ESCA.
For his research on electron spectroscopy, Kai Siegbahn was awarded the Nobel Prize in Physics 1981. He shared the prize with N. Bloembergen and A. Schawlow from the US.
Today: In Uppsala world-leading research is being conducted based on further developed electron spectroscopy with many applications. Research in physics and astronomy stretches from string theory, particle physics and nuclear physics via atomic physics and materials science to the origin of our solar system and the entire universe. Uppsala is an active participant in a great number of leading national and international research collaborations such as the European particle physics laboratory CERN and MAXLab in Lund which is a national research laboratory using synchrotron radiation.