Difference between revisions of "Absorption edge"
From Online Dictionary of Crystallography
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| − | < | + | <font color="blue">Arête d'absorption</font> (''Fr''). <font color="red">Absorptionskante</font> (''Ge''). <font color="black">Spigolo di assorbimento</font>(''It''). <font color="purple">吸収端</font> (''Ja''). <font color="purple">край поглощения</font> (''Ru''). <font color="green">Canto de absorción</font> (''Sp''). |
== Definition == | == Definition == | ||
Revision as of 17:37, 8 November 2017
Arête d'absorption (Fr). Absorptionskante (Ge). Spigolo di assorbimento(It). 吸収端 (Ja). край поглощения (Ru). Canto de absorción (Sp).
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 for Crystallography, Volume C