Difference between revisions of "Absorption edge"
From Online Dictionary of Crystallography
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== Definition == | == Definition == | ||
| − | An absorption edge is a sharp discontinuity in the absorption | + | An absorption edge is the energy at which there is a sharp rise (discontinuity) in the (linear) absorption coefficient of X-rays by an element, which occurs when the energy of the photon corresponds to the energy of a shell of the atom (''K'', ''L<sub>I</sub>'', ''L<sub>II</sub>'', ''L<sub>III</sub>'', ''etc.'' corresponding to the creation of electron holes in the 122s22, 2''s'', 2''p''<sub>1/2</sub>, 2''p''<sub>3/2</sub> ''etc.'' atomic subshells). |
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| + | Associated with this transition is the absorption threshold (''q.v.'') characterized by the corresponding energy ''E''<sub>0</sub>. | ||
== Examples == | == Examples == | ||
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== See also == | == See also == | ||
| − | Section 4.2.3 of ''International Tables of Crystallography, Volume C'' | + | *[[Absorption threshold]] |
| + | *[[Fermi level]] | ||
| + | *Section 4.2.3 of ''International Tables of Crystallography, Volume C'' | ||
[[Category:X-rays]] | [[Category:X-rays]] | ||
[[Category: X-ray absorption spectroscopy]] | [[Category: X-ray absorption spectroscopy]] | ||
Revision as of 15:45, 12 April 2016
Discontinuité, arête d'absorption (Fr). Absorptionskante (Ge). Canto de absorción (Sp). край поглощения (Ru). Spigolo di assorbimento (It). 吸収端 (Ja)
Definition
An absorption edge is the energy at which there is a sharp rise (discontinuity) in the (linear) absorption coefficient of X-rays by an element, which occurs when the energy of the photon corresponds to the energy of a shell of the atom (K, LI, LII, LIII, etc. corresponding to the creation of electron holes in the 122s22, 2s, 2p1/2, 2p3/2 etc. atomic subshells).
Associated with this transition is the absorption threshold (q.v.) characterized by the corresponding energy E0.
Examples
For gallium: [math]\lambda_{K}[/math] = 1.1958 Ǻ; [math]\lambda_{L_{I}}[/math] = 9.5446 Ǻ; [math]\lambda_{L_{II}}[/math] = 10.8414 Ǻ; [math]\lambda_{L_{III}}[/math]= 11.1038 Ǻ;
For arsenic: [math]\lambda_{K}[/math] = 1.0448 Ǻ; [math]\lambda_{L_{I}}[/math] = 8.1195 Ǻ; [math]\lambda_{L_{II}}[/math] = 9.1187 Ǻ; [math]\lambda_{L_{III}}[/math]= 9.3617 Ǻ;
See also
- Absorption threshold
- Fermi level
- Section 4.2.3 of International Tables of Crystallography, Volume C