History
The first evidence of quantized energy levels in atoms was the observation of spectral lines in light from the sun in the early 1800s by Joseph von Fraunhofer and William Hyde Wollaston. The theoretical explanation for energy levels was discovered in 1913 by Danish physicist Neils Bohr in the Bohr theory of the atom. The modern quantum mechanical theory, based on the Schrodinger equation, was advanced by Erwin Schrodinger and Werner Heisenberg in 1926.
Read more about this topic: Energy Level
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