Systematic absences

From Online Dictionary of Crystallography

(Difference between revisions)
Jump to: navigation, search
Line 1: Line 1:
-
<Font color="blue">absences systématiques</Font> (''Fr'').
+
<Font color="blue">Absences systématiques</Font> (''Fr''). <Font color="green"> Extinciones sistemáticas </Font> (''Sp'').
== Definition ==
== 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]].
+
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 ==

Revision as of 08:05, 17 April 2006

Absences systématiques (Fr). 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
Sections 2.2.13 and 12.3.5 of the International Tables of Crystallography (Volume A)