Johannes Stark measured the splitting of atomic spectral lines in a strong electric field. The Stark effect connects that applied field with changes in atomic energy levels and therefore the frequencies of emitted light. Resolving the splitting requires control of the electric field, the emitting region and the spectral resolution. Different observed components need not shift equally: the pattern tests how the electric perturbation changes the available quantum states, rather than merely showing that the light source is affected.[ref]
Observation of the Separation of Spectral Lines by an Electric Field by Johannes Stark. 1913 experimental communication
[ref]Structural and Spectral Changes of Chemical Atoms by Johannes Stark. Nobel lecture: electric-field effects on spectra
Portrait of Johannes Stark
. A. B. Lagrelius & Westphal, Stockholm; Les Prix Nobel 1919 (1920), p. 121; Nobel Foundation source. Commons PD-Sweden photograph claim. File requests an additional United States public-domain tag; worldwide status is not asserted., via Wikimedia Commons. Source. Articles by others on the same topic
Johannes Stark (1874–1957) was a German physicist known for his work in the field of experimental physics. He is especially recognized for his research in the areas of atomic and molecular spectroscopy. One of his most notable contributions is the Stark effect, which describes the splitting of spectral lines of atoms and molecules in an external electric field. This effect is significant in the study of the behavior of atoms in electric fields and has various applications in physics and chemistry.