Method of Steepest Descents in X-Ray Analysis

Method of Steepest Descents in X-Ray Analysis

IN the method of steepest descents, atomic co-ordinates are derived by minimizing a function of the observed and calculated structure amplitudes. Hughes1 minimizes Σw (F0 - Fc)2, where the weighting factors are w ∼ 1/F02 when F0 > 4 Ft, and w ∼ 1/16 Ft2 when F0 < 4 Ft ; Ft is the threshold val...

Ausführliche Beschreibung

Gespeichert in:
Bibliographische Detailangaben
Veröffentlicht in:Nature (London) 1949-01, Vol.163 (4134), p.129-130
1. Verfasser: VAND, V
Format: Artikel
Sprache:eng
Schlagworte:
Humans
Old Medline
X-Rays - methods
Online-Zugang:Volltext
Tags: Tag hinzufügen
Keine Tags, Fügen Sie den ersten Tag hinzu!
Beschreibung
Zusammenfassung:IN the method of steepest descents, atomic co-ordinates are derived by minimizing a function of the observed and calculated structure amplitudes. Hughes1 minimizes Σw (F0 - Fc)2, where the weighting factors are w ∼ 1/F02 when F0 > 4 Ft, and w ∼ 1/16 Ft2 when F0 < 4 Ft ; Ft is the threshold value of the measurement. As the errors do not obey Gauss' law, this formula does not give the best least-squares solution.
ISSN:0028-0836
1476-4687
DOI:10.1038/163129b0