Tables for
Volume F
Crystallography of biological macromolecules
Edited by M. G. Rossmann and E. Arnold

International Tables for Crystallography (2006). Vol. F, ch. 16.1, p. 334   | 1 | 2 |

Section SAS differences

G. M. Sheldrick,c H. A. Hauptman,b C. M. Weeks,b* R. Millerb and I. Usóna

aInstitut für Anorganisch Chemie, Universität Göttingen, Tammannstrasse 4, D-37077 Göttingen, Germany,bHauptman–Woodward Medical Research Institute, Inc., 73 High Street, Buffalo, NY 14203-1196, USA, and cLehrstuhl für Strukturchemie, Universität Göttingen, Tammannstrasse 4, D-37077 Göttingen, Germany
Correspondence e-mail: SAS differences

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Given Friedel pairs of normalized structure-factor magnitudes [(|E_{+{\bf H}}|, |E_{-{\bf H}}|)] and the atomic scattering factors, then the greatest-lower-bound estimates of SAS difference [|E|]'s are [{|E_{\Delta}| = {\left[\textstyle\sum_{j=1}^{N}\displaystyle (\;f_{j}^{0} + f_{j}^{'})^{2} + (\;f_{j}^{''})^{2}\right]^{1/2} \|E_{+{\bf H}}| - |E_{-{\bf H}}\| \over 2q\left[\textstyle\sum_{j=1}^{N}\displaystyle (\;f_{j}^{''})^{2}\right]^{1/2}}}, \eqno(] where, again, q is an empirical renormalization scaling function that imposes the condition [\langle |E_{\Delta}|^{2}\rangle = 1].

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