Anomalous scattering - Revision history

BrianMcMahon: Tidied translations.

2017-11-08T17:58:40Z

Tidied translations.

BrianMcMahon: Style edits to align with printed edition

2017-05-12T11:57:00Z

Style edits to align with printed edition

MassimoNespolo: Ja

2015-03-04T05:29:39Z

BrianMcMahon: Tidying layout

2012-02-03T15:54:31Z

Tidying layout

AndreAuthier at 06:06, 18 March 2006

2006-03-18T06:06:52Z

GiovanniFerraris at 15:16, 17 March 2006

2006-03-17T15:16:29Z

BrianMcMahon at 10:48, 25 January 2006

2006-01-25T10:48:11Z

New page

= Anomalous scattering =

=== Other languages ===

Diffusion anomale (''Fr''). Anomale Streuung (''Ge''). Difusión anómala (''Sp'').

== Definition ==

The history of the description of the scattering of an atom when illuminated with X-rays is that initially wavelength dependencies were ignored. This was initially referred to as 'normal scattering'. The wavelength dependencies were then corrections to the normal scattering and also called anomalous. These had to describe changes in amplitude and phase, respectively initially given the symbols <math>\Delta f\,'</math> and <math>\Delta f\,''</math>. Thus the X-ray scattering factor of an atom is described by the equation:-

<math>f=f_o + \Delta f\,' + i\Delta f\,''</math>

The nomenclature changed when tunable synchrotron sources became available and whereby the <math>\Delta</math> prefixes were removed because changes between two wavlengths would then have required a double Δ label, which is cumbersome. Thus the <math>\Delta f\,'</math> now means the change in <math>f\,'</math> between two wavelengths. The <math>\Delta</math> prefix to <math>f\,''</math> is dropped for consistency even though its use is based on its value at a single wavelength.

The values of <math>f\,'</math> and <math>f\,''</math> change most at the absorption edge of the element in question. Thus this resonance effect sometimes leads to the term being refererred to as 'resonant scattering'. However, since the off resonance <math>f\,''</math> effect is extensively used in crystal structure determination of the hand of a molecule (its chirality) 'anomalous scattering' is the best ''i.e.'' most widely embracing term. Another commonly used term is Multiple-wavelength Anomalous Dispersion ('MAD'), which involves measurements made at the resonance condition and at more than one wavelength obviously.

=== See also ===

[[anomalous dispersion]]<br>
[[resonant scattering]]<br>
[[multiwavelength anomalous diffraction (MAD)]]<br>

----
[[Category:X-rays]]<br>

← Older revision		Revision as of 17:58, 8 November 2017
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−	<~~Font~~ color="blue">Diffusion anomale</~~Font~~> (''Fr''). <~~Font~~ color="red">Anomale Streuung</~~Font~~> (''Ge''). <~~Font~~ color="~~green~~">~~Difusión anómala~~</~~Font~~> (''Sp''). <~~Font~~ color="~~black~~"> ~~Diffusione anomala~~ </~~Font~~>(''It''). <~~Font~~ color="~~purple~~"> ~~異常散乱~~ </~~Font~~>(''Ja'').	+	<font color="blue">Diffusion anomale</font> (''Fr''). <font color="red">Anomale Streuung</font> (''Ge''). <font color="black">Diffusione anomala</font> (''It''). <font color="purple">異常散乱</font> (''Ja''). <font color="green">Difusión anómala</font> (''Sp'').

	== Definition ==		== Definition ==

← Older revision		Revision as of 05:29, 4 March 2015
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−	<Font color="blue">Diffusion anomale</Font> (''Fr''). <Font color="red">Anomale Streuung </Font>(''Ge''). <Font color="green">Difusión anómala (</Font>''Sp''). <Font color="black"> Diffusione anomala </Font>(''It'')	+	<Font color="blue">Diffusion anomale</Font> (''Fr''). <Font color="red">Anomale Streuung </Font>(''Ge''). <Font color="green">Difusión anómala (</Font>''Sp''). <Font color="black"> Diffusione anomala </Font>(''It''). <Font color="purple"> 異常散乱 </Font>(''Ja'')

	== Definition ==		== Definition ==

← Older revision		Revision as of 06:06, 18 March 2006
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−	= ~~Anomalous scattering =~~	+	<Font color="blue">Diffusion anomale</Font> (''Fr''). <Font color="red">Anomale Streuung </Font>(''Ge''). <Font color="green">Difusión anómala (</Font>''Sp''). <Font color="black"> Diffusione anomala </Font>(''It'')
−
−
−	~~=== Other languages ===~~
−
−	Diffusion anomale (''Fr''). Anomale Streuung (''Ge''). Difusión anómala (''Sp''). <Font color="black"> Diffusione anomala </Font>(''It'')

← Older revision		Revision as of 15:16, 17 March 2006
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	=== Other languages ===		=== Other languages ===

−	Diffusion anomale (''Fr''). Anomale Streuung (''Ge''). Difusión anómala (''Sp'').	+	Diffusion anomale (''Fr''). Anomale Streuung (''Ge''). Difusión anómala (''Sp''). <Font color="black"> Diffusione anomala </Font>(''It'')
		+

@@ Line 1: / Line 1: @@
-<Font color="blue">Diffusion anomale</Font> (''Fr''). <Font color="red">Anomale Streuung </Font>(''Ge''). <Font color="green">Difusión anómala (</Font>''Sp''). <Font color="black"> Diffusione anomala </Font>(''It''). <Font color="purple"> 異常散乱 </Font>(''Ja'')
+<Font color="blue">Diffusion anomale</Font> (''Fr''). <Font color="red">Anomale Streuung</Font> (''Ge''). <Font color="green">Difusión anómala</Font> (''Sp''). <Font color="black"> Diffusione anomala </Font>(''It''). <Font color="purple"> 異常散乱 </Font>(''Ja'').
 == Definition ==
-The history of the description of the scattering of an atom when illuminated with X-rays is that initially wavelength dependencies were ignored. This was initially referred to as 'normal scattering'. The wavelength dependencies were then corrections to the normal scattering and also called anomalous. These had to describe changes in amplitude and phase, respectively initially given the symbols <math>\Delta f\,'</math>  and <math>\Delta f\,''</math>. Thus the X-ray scattering factor of an atom is described by the equation:-
+The history of the description of the scattering of an atom when illuminated with X-rays is that initially wavelength dependencies were ignored. This was initially referred to as 'normal scattering'. The wavelength dependencies were then corrections to the normal scattering and also called anomalous. These had to describe changes in amplitude and phase, respectively initially given the symbols <math>\Delta f\,'</math>  and <math>\Delta f\,''</math>. Thus the X-ray scattering factor of an atom is described by the equation
-<math>f=f_o + \Delta f\,' + i\Delta f\,''</math>
+<math>f=f_o + \Delta f\,' + i\Delta f\,''.</math>
-The nomenclature changed when tunable synchrotron sources became available and whereby the <math>\Delta</math> prefixes were removed because changes between two wavlengths would then have required a double &#916; label, which is cumbersome. Thus the <math>\Delta f\,'</math> now means the change in <math>f\,'</math> between two wavelengths. The <math>\Delta</math> prefix to <math>f\,''</math> is dropped for consistency even though its use is based on its value at a single wavelength.
+The nomenclature changed when tunable synchrotron sources became available and the <math>\Delta</math> prefixes were removed because changes between two wavelengths would then have required a double <math>\Delta</math> label, which is cumbersome. Thus the <math>\Delta f\,'</math> now means the change in <math>f\,'</math> between two wavelengths. The <math>\Delta</math> prefix to <math>f\,''</math> is dropped for consistency even though its use is based on its value at a single wavelength.
-The values of <math>f\,'</math> and <math>f\,''</math> change most at the absorption edge of the element in question. Thus this resonance effect sometimes leads to the term being refererred to as 'resonant scattering'. However, since the off resonance <math>f\,''</math> effect is extensively used in crystal structure determination of the hand of a molecule (its chirality) 'anomalous scattering' is the best ''i.e.'' most widely embracing term. Another commonly used term is Multiple-wavelength Anomalous Dispersion ('MAD'), which involves measurements made at the resonance condition and at more than one wavelength obviously.
+The values of <math>f\,'</math> and <math>f\,''</math> change most at the absorption edge of the element in question. Thus this resonance effect sometimes leads to the term being referred to as 'resonant scattering'. However, since the off resonance <math>f\,''</math> effect is extensively used in crystal structure determination of the hand of a molecule (its chirality) 'anomalous scattering' is the best ''i.e.'' most widely embracing term. Another commonly used term is Multiple-wavelength Anomalous Dispersion ('MAD'), which involves measurements made at the resonance condition and at more than one wavelength obviously.
 === See also ===
-[[anomalous dispersion]]<br>
+*[[Anomalous dispersion]]
-[[resonant scattering]]<br>
+*[[Resonant scattering]]
-[[multiwavelength anomalous diffraction (MAD)]]<br>
+*[[Multiwavelength anomalous diffraction (MAD)]]
 [[Category:X-rays]]<br>