Siegbahn notation
Notation in X-ray spectroscopy
The Siegbahn notation is used in X-ray spectroscopy to name the spectral lines that are characteristic to elements. It was introduced by Manne Siegbahn.
The characteristic lines in X-ray emission spectra correspond to atomic electronic transitions where an electron jumps down to a vacancy in one of the inner shells of an atom. Such a hole in an inner shell may have been produced by bombardment with electrons in an X-ray tube, by other particles as in PIXE, by other X-rays in X-ray fluorescence or by radioactive decay of the atom's nucleus.
Although still widely used in spectroscopy, this notation is unsystematic and often confusing. For these reasons, International Union of Pure and Applied Chemistry (IUPAC) recommends another nomenclature.
01History
The use of the letters K and L to denote X-rays originates in a 1911 paper by Charles Glover Barkla, titled The Spectra of the Fluorescent Röntgen Radiations ("Röntgen radiation" is an archaic name for "X-rays"). These letters, in the middle of the alphabet, were chosen over A and B to allow for the possibility that further series of X-rays, both more and less penetrating, would subsequently be discovered. By 1913, Henry Moseley had clearly differentiated two types of X-ray lines for each element, naming them α and β. In 1914, as part of his thesis, Ivar Malmer (sv:Ivar Malmer), a student of Manne Siegbahn, discovered that the α and β lines were not single lines, but doublets. In 1916, Siegbahn published this result in the journal Nature, using what would come to be known as the Siegbahn notation.
02Correspondence between the Siegbahn and IUPAC notations
The table below shows a few transitions and their initial and final levels.
| Initial level | Final level | Siegbahn notation | IUPAC notation |
|---|---|---|---|
| K (1s1/2−1) | L3 (2p3/2−1) | Kα1 | K-L3 |
| L2 (2p1/2−1) | Kα2 | K-L2 | |
| M3 (3p3/2−1) | Kβ1 | K-M3 | |
| M2 (3p1/2−1) | Kβ3 | K-M2 | |
| L3 (2p3/2−1) | M5 (3d5/2−1) | Lα1 | L3, M5 |
| M4 (3d3/2−1) | Lα2 | L3, M4 | |
| L2 (2p1/2−1) | M4 (3d3/2−1) | Lβ1 | L2, M4 |
| M5 (3d5/2−1) | N7 (4f7/2−1) | Mα1 | M5, N7 |
Sources and credits
This article is adapted from the Wikipedia article “Siegbahn notation”, written by its contributors and licensed under CC BY-SA 4.0. Fathomly has changed the layout, removed citation markers, navigation and maintenance notices, and adjusted punctuation. This adapted version is shared under the same license. For references, see the original article.
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