Закон Мозли для характеристического рентгеновского излучения атомов

Law concerning X rays emitted by atoms

Moseley's law is an empirical law concerning the characteristic X rays emitted by atoms. The law had been discovered and published by the English physicist Henry Moseley in 1913–1914. In brief, the law states that the square root of the frequency of the emitted X ray is approximately proportional to the atomic number:

The historic periodic table was roughly ordered by increasing atomic weight, but in a few famous cases the physical properties of two elements suggested that the heavier ought to precede the lighter. An example is cobalt having the atomic weight of 58.9 and nickel having the atomic weight of 58.7. Henry Moseley and other physicists used X ray diffraction to study the elements, and the results of their experiments led to organizing the periodic table by proton count.

Since the spectral emissions for the lighter elements would be in the soft X ray range (absorbed by air), the spectrometry apparatus had to be enclosed inside a vacuum. Details of the experimental setup are documented in the journal articles "The High Frequency Spectra of the Elements" Part I and Part II.

Moseley found that the lines (in Siegbahn notation) were indeed related to the atomic number, Z. An elaborate discussion criticizing Moseley's interpretation of screening can be found in a paper by Whitaker which is repeated in most modern texts. A list of experimentally found and theoretically calculated X ray transition energies is available at NIST. Nowadays, theoretical energies are computed with a much greater accuracy than what Moseley's law provides, using modern computational models such as the Dirac–Fock method (the Hartree–Fock method with the relativistic effects accounted for).