Resolution d'un structure cristalline lorsque les positions d'une partie des atoms sont connues: traitement statistique

Abstract

A statistical method has been applied to develop the relation between the electron density and a function '(r) calculated with the moduli of the structure factors corresponding to all the atoms in the unit cell of a crystal and with phase angles corresponding to only some of these atoms. Both centrosymmetrical artd non-centrosymmetrical cases are considered and a criterion is proposed which makes it possible to predict whether or not the positions of all the atoms in a structure can be determined when the positions of some of them are known.