31 citations · 144 across the 35 of their papers we have counts for
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An early explanation of the periodic table: Lars Vegard and X-ray spectroscopy
Helge Kragh
The Norwegian physicist Lars Vegard may have been the first to propose electron configurations for all the chemical elements, from hydrogen to uranium, on the basis of quantum atom…
Spreading the gospel: The Bohr atom popularised
Helge Kragh, Kristian Hvidtfelt Nielsen
The emergence of quantum theory in the early decades of the twentieth century was accompanied by a wide range of popular science books, all of which presented in words and in image…
The isotope effect: Prediction, discussion, and discovery
Helge Kragh
The precise position of a spectral line emitted by an atomic system depends on the mass of the atomic nucleus and is therefore different for isotopes belonging to the same element.…
Visions of Revolutions: Microphysics and Cosmophysics in the 1930s
Helge Kragh
By 1930, at a time when the new physics based on relativity and quantum theory had reached a state of consolidation, problems of a foundational kind began to abound. Physicists beg…
Preludes to dark energy: Zero-point energy and vacuum speculations
Helge Kragh
Although dark energy is a modern concept, some elements in it can be traced back to the early part of the twentieth century. This paper examines the origin of the idea of zero-poin…