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(<Font color="blue">Discontinuité, arête d'absorption</Font> (''Fr''). <Font color="red"> Absorptionskante </Font> (''Ge''). <Font color="green">Canto de absorción</Font> (''Sp''). <Font color="purple">край поглощения</Font> (''Ru''). <Font color="black">Spigolo di assorbimento </Font>(''It'')
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<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 spectrum of X-rays by an element that 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.).  
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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 ==
 
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;
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<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;
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<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 of Crystallography, Volume C''
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*[[Absorption threshold]]
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*[[Fermi level]]
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*Section 4.2.3 of ''International Tables for Crystallography, Volume C''
  
[[Category:X-rays]]<br>
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[[Category:X-rays]]
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[[Category: X-ray absorption spectroscopy]]

Revision as of 16:10, 27 November 2017

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 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