Difference between revisions of "Absorption edge"
From Online Dictionary of Crystallography
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== Definition == | == 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'', ''L<sub>I</sub>'', ''L<sub>II</sub>'', ''L<sub>III</sub>'', ''etc.'' corresponding to the creation of electron holes in the | + | 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 1''s'', 2''s'', 2''p''<sub>1/2</sub>, 2''p''<sub>3/2</sub> ''etc.'' atomic subshells). |
Associated with this transition is the absorption threshold (''q.v.'') characterized by the corresponding energy ''E''<sub>0</sub>. | Associated with this transition is the absorption threshold (''q.v.'') characterized by the corresponding energy ''E''<sub>0</sub>. | ||
Latest revision as of 12:45, 3 November 2020
حافة امتصاص (Ar). 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 1s, 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