Direkte Methoden für Strukturen mit schwach ausgeprägten Überstruktureffekten — Verhalten der Hauptreflexe

Abstract

For structures with approximate pseudotranslational symmetry the £-values obtained by a renormalizing procedure are investigated. Specially for main reflections the mean scattering power of point-atoms is considered as a function dependent on sin θ/λ and on how far the atoms in the structure deviate from ideal symmetry. For sin θ/λ -ranges in which the scattering power is a constant function classical probabilistic distributions are available. The effects are demonstrated for some real structures which were difficult or not to solve via direct methods procedures because they suffer under weak rational dependencies between their atoms.Einleitung