Difference between revisions of "Absorption edge"
From Online Dictionary of Crystallography
AndreAuthier (talk | contribs) |
BrianMcMahon (talk | contribs) m (→Definition) |
||
| (9 intermediate revisions by 2 users not shown) | |||
| Line 1: | Line 1: | ||
| − | (< | + | <font color="orange">حافة امتصاص</font> (''Ar''). <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="brown">край поглощения</font> (''Ru''). <font color="green">Canto de absorción</font> (''Sp''). |
| − | |||
| − | |||
== 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 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>. | ||
== Examples == | == Examples == | ||
| − | |||
For gallium: | 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. | |
| − | <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: | 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. | |
| − | <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 == | == See also == | ||
| − | Section 4.2.3 of ''International Tables | + | *[[Absorption threshold]] |
| − | + | *[[Fermi level]] | |
| + | *Section 4.2.3 of ''International Tables for Crystallography, Volume C'' | ||
| − | [[Category:X-rays]] | + | [[Category:X-rays]] |
| + | [[Category: X-ray absorption spectroscopy]] | ||
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