Pseudo symmetry - Revision history

BrianMcMahon: Tidied translations and added German and Spanish (U. Mueller)

2017-11-17T10:12:15Z

Tidied translations and added German and Spanish (U. Mueller)

BrianMcMahon: Style edits to align with printed edition

2017-05-16T13:34:06Z

Style edits to align with printed edition

MassimoNespolo: typo (wrong sinograph)

2016-09-20T14:11:41Z

typo (wrong sinograph)

MassimoNespolo at 15:37, 16 April 2015

2015-04-16T15:37:07Z

MassimoNespolo at 17:37, 28 December 2008

2008-12-28T17:37:46Z

New page

Pseudo symmetry
Pseudo symétrie (Fr); Pseudo simmetria locale (It); 疑対称 (Ja)

A crystal space can in general be divided in ''N'' components S1 to S''N''. When a coincidence operation φ(S''i'')→S''j'' brings the ''i''-th component S''i'' to coincide with the ''j''-th component S''j'', for any ''i'' and ''j'', φ is a symmetry operation of the [[space group]].

Sometimes, φ brings S''i'' close to, but not exactly on, the position and orientation of S''j'': in this case the operation mapping S''i'' onto S''j'' is [[Noncrystallographic symmetry|not crystallographic]] but the linear and/or rotational deviation from a space group operation is limited. For this reason, it is preferable to describe the crystallographic operation φ as a '''pseudo symmetry operation'''.

Pseudo symmetry operations for the lattice play an important role in twinning, namely in the case of [[twinning by pseudomerohedry]] and [[twinning by reticular pseudomerohedry]].

[[Category: Fundamental crystallography]]

← Older revision		Revision as of 10:12, 17 November 2017
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−	<font color="blue">Pseudo symétrie</font> (<i>Fr</i>). <font color="black">Pseudo simmetria</font> (~~<i>~~It~~</i>~~). <font color="purple">擬対称</font> (<i>Ja</i>).	+	<font color="blue">Pseudo symétrie</font> (''Fr''). <font color="red">Pseudosymmetrie</font> (''Ge''). <font color="black">Pseudo simmetria</font> (''It''). <font color="purple">擬対称</font> (''Ja''). <font color="green">Seudosimetría</font> (''Sp'').

@@ Line 1: / Line 1: @@
-<font color="blue">Pseudo symétrie</font> (<i>Fr</i>); <font color="black">Pseudo simmetria</font> (<i>It</i>); <font color="purple">擬対称</font> (<i>Ja</i>)
+<font color="blue">Pseudo symétrie</font> (<i>Fr</i>). <font color="black">Pseudo simmetria</font> (<i>It</i>). <font color="purple">擬対称</font> (<i>Ja</i>).
-A crystal space can in general be divided in ''N'' components S<sub>1</sub> to S<sub>''N''</sub>. When a coincidence operation &phi;(S<sub>''i''</sub>)&rarr;S<sub>''j''</sub> brings the ''i''-th component S<sub>''i''</sub> to coincide with the ''j''-th component S<sub>''j''</sub>, for any ''i'' and ''j'', &phi; is a symmetry operation of the [[space group]].
+A crystal space can in general be divided in ''N'' components ''S''<sub>1</sub> to ''S''<sub>''N''</sub>. When a coincidence operation &phi;(''S''<sub>''i''</sub>)&rarr;''S''<sub>''j''</sub> brings the ''i''th component ''S''<sub>''i''</sub> to coincide with the ''j''th component ''S''<sub>''j''</sub>, for any ''i'' and ''j'', &phi; is a symmetry operation of the [[space group]].
-Sometimes, &phi; brings S<sub>''i''</sub> close to, but not exactly on, the position and orientation of S<sub>''j''</sub>: in this case the operation mapping S<sub>''i''</sub> onto S<sub>''j''</sub> is [[Noncrystallographic symmetry|not crystallographic]] but the linear and/or rotational deviation from a space group operation is limited. For this reason, it is preferable to describe the crystallographic operation &phi; as a '''pseudo symmetry operation'''.
+Sometimes, &phi; brings ''S''<sub>''i''</sub> close to, but not exactly on, the position and orientation of ''S''<sub>''j''</sub>; in this case the operation mapping ''S''<sub>''i''</sub> onto ''S''<sub>''j''</sub> is [[Noncrystallographic symmetry|not crystallographic]] but the linear and/or rotational deviation from a space group operation is limited. For this reason, it is preferable to describe the crystallographic operation &phi; as a '''pseudo symmetry operation'''.
 Pseudo symmetry operations for the lattice play an important role in twinning, namely in the case of [[twinning by pseudomerohedry]] and [[twinning by reticular pseudomerohedry]].

← Older revision		Revision as of 14:11, 20 September 2016
Line 1:		Line 1:
−	<font color="blue">Pseudo symétrie</font> (<i>Fr</i>); <font color="black">Pseudo simmetria</font> (<i>It</i>); <font color="purple">~~疑対称~~</font> (<i>Ja</i>)	+	<font color="blue">Pseudo symétrie</font> (<i>Fr</i>); <font color="black">Pseudo simmetria</font> (<i>It</i>); <font color="purple">擬対称</font> (<i>Ja</i>)

← Older revision		Revision as of 15:37, 16 April 2015
Line 1:		Line 1:
−	~~Pseudo symmetry~~	+	<font color="blue">Pseudo symétrie</font> (<i>Fr</i>); <font color="black">Pseudo simmetria</font> (<i>It</i>); <font color="purple">疑対称</font> (<i>Ja</i>)
−	<font color="blue">Pseudo symétrie</font> (<i>Fr</i>); <font color="black">Pseudo simmetria ~~locale~~</font> (<i>It</i>); <font color="purple">疑対称</font> (<i>Ja</i>)