November 8, 1854|
|Died||December 28, 1919
|Known for||Rydberg formula|
|Notable awards||Fellow of the Royal Society (1919)|
Johannes (Janne) Robert Rydberg (November 8, 1854 – December 28, 1919) was a Swedish physicist mainly known for devising the Rydberg formula, in 1888, which is used to predict the wavelengths of photons (of light and other electromagnetic radiation) emitted by changes in the energy level of an electron in a hydrogen atom.
The physical constant known as the Rydberg constant is named after him, as is the Rydberg unit. Excited atoms with very high values of the principal quantum number, represented by n in the Rydberg formula, are called Rydberg atoms. Rydberg's anticipation that spectral studies could assist in a theoretical understanding of the atom and its chemical properties was justified in 1913 by the work of Niels Bohr (see hydrogen spectrum). An important spectroscopic constant based on a hypothetical atom of infinite mass is called the Rydberg (R) in his honour.
See also 
- Sutton, Mike. “Getting the numbers right – the lonely struggle of Rydberg.” Chemistry World, Vol. 1, No. 7, July 2004.
- Martinson, Indrek; L.J. Curtis (2005). "Janne Rydberg – his life and work". NIM B 235: 17–22. Bibcode:2005NIMPB.235...17M. doi:10.1016/j.nimb.2005.03.137.
- The Rydbergs Källare homepage (in Swedish).
- O'Connor, John J.; Robertson, Edmund F., "Johannes Rydberg", MacTutor History of Mathematics archive, University of St Andrews.