International
Tables for
Crystallography
Volume B
Reciprocal space
Edited by U. Shmueli

© International Union of Crystallography 2006
International Tables for Crystallography (2006). Vol. B. ch. 2.2, p. 216   | 1 | 2 |

Section 2.2.4.2. Definition of quasi-normalized structure factor

C. Giacovazzoa*

aDipartimento Geomineralogico, Campus Universitario, I-70125 Bari, Italy
Correspondence e-mail: c.giacovazzo@area.ba.cnr.it

2.2.4.2. Definition of quasi-normalized structure factor

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When probability theory is not used, the quasi-normalized structure factors [ \hbox{\scr E}_{\bf h}] and the unitary structure factors [U_{\bf h}] are often used. [ \hbox{\scr E}_{\bf h}] and [U_{\bf h}] are defined according to [ \eqalign{|\hbox{\scr E}_{\bf h}|^{2} &= \varepsilon_{\bf h}|E_{\bf h}|^{2}\cr U_{\bf h} &= F_{\bf h} \Big/ \left(\textstyle\sum\limits_{j=1}^{N} f_{j}\right).}] Since [\sum_{j=1}^{N} f_{j}] is the largest possible value for [F_{\bf h}, U_{\bf h}] represents the fraction of [F_{\bf h}] with respect to its largest possible value. Therefore [0 \leq |U_{\bf h}| \leq 1.] If atoms are equal, then [ U_{\bf h} = \hbox{\scr E}_{\bf h} / N^{1/2}].








































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