Well, the question arose in the physics chat when slereah mentioned about it.

So, was there any prominent model that came to light after Bohr and before the actual beginning of Quantum Mechanics in early 20s?

As Slereah mentions:

History of physics texts rarely mention models of that era

What were the developments in this topic during that specific period?

  • $\begingroup$ What about Sommerfeld's atom model, or are you considering this as being within Bohr's model? I don't know about currently used texts, but the Sommerfeld model was mentioned in pretty much all the U.S. Sophomore level modern physics texts when I was an undergrdaduate in the 1970s. In fact, I believe it was even mentioned in my high school physics text. $\endgroup$ Commented Jul 11, 2016 at 16:48
  • 1
    $\begingroup$ There was the BKS theory, which was a mess and died at the age of about three: en.wikipedia.org/wiki/BKS_theory The fundamental issue that was confusing people in this period was that Bohr kept insisting that the atom should be quantized but that radiation should be classical. This leads to nonconservation of energy and momentum, except on a statistical basis, and that prediction was how the theory was disproved by Bothe and Geiger ca 1925. $\endgroup$
    – user466
    Commented Jul 11, 2016 at 19:15
  • $\begingroup$ @BenCrowell: I might want to see this as an answer. $\endgroup$
    – user1709
    Commented Jul 11, 2016 at 19:18

1 Answer 1


To my knowledge the first documented atomic model considering Planck’s action quantum was formulated by the Austrian Arthur Erich Haas (1884-1941). He hypothesized in 1910 a relation between the action quantum and the size of atoms. A substantial initiation progress was postulated by John William Nicholson (1881-1955) (Cambridge) who in 1912 formulated the quantization of angular momentum and conjectured an explanation of Ritz’s series rule of hydrogen spectra. (shortly before Niels Bohr’s model). In conclusion, Niels Bohr wasn’t the first to formulate a relationship between the quantum of action and the atomic structure. However Bohr soon became friend of Nicholson who must have inspired him. The whole story of the many try-and-error attempts of Bohr’s atomic model are documented in a trilogy published in “The Philosophical magazine” July 26, 1913.


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