Systematic absences: Difference between revisions
From Online Dictionary of Crystallography
AndreAuthier (talk | contribs) No edit summary |
BrianMcMahon (talk | contribs) Added German and Spanish translations (U. Mueller) |
||
| (9 intermediate revisions by 4 users not shown) | |||
| Line 1: | Line 1: | ||
< | <font color="blue">Absences systématiques</font> (''Fr''). <font color="red">Systematische Auslöschungen</font> (''Ge''). <font color="black">Assenze sistematiche, estinzioni sistematiche</font>(''It''). <font color="purple">消滅則</font> (''Ja''). <font color="green">Ausencias sistemáticas, extinciones sistemáticas</font> (''Sp''). | ||
== Definition == | == Definition == | ||
One speaks of ''systematic absences'' or '' | One speaks of ''systematic absences'' or ''extinctions'' when the structure factor is zero, due either to the centring of the lattice or to the presence of glide or screw symmetry elements. Conversely, the conditions for a reflection to exist and not to be systematically absent, are called [[reflection conditions]]. | ||
== See also == | == See also == | ||
*[[Reflection conditions]] | |||
*Chapter 1.6.4 of ''International Tables for Crystallography, Volume A'', 6th edition | |||
[[ | [[Category:X-rays]] | ||
Latest revision as of 09:22, 20 November 2017
Absences systématiques (Fr). Systematische Auslöschungen (Ge). Assenze sistematiche, estinzioni sistematiche(It). 消滅則 (Ja). Ausencias sistemáticas, extinciones sistemáticas (Sp).
Definition
One speaks of systematic absences or extinctions when the structure factor is zero, due either to the centring of the lattice or to the presence of glide or screw symmetry elements. Conversely, the conditions for a reflection to exist and not to be systematically absent, are called reflection conditions.
See also
- Reflection conditions
- Chapter 1.6.4 of International Tables for Crystallography, Volume A, 6th edition