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International
Tables for Crystallography Volume G Definition and exchange of crystallographic data Edited by S. R. Hall and B. McMahon © International Union of Crystallography 2006 |
International Tables for Crystallography (2006). Vol. G. ch. 3.2, pp. 105-106
Section 3.2.4.1.2. Collections of atom sites
a
School of Biomedical and Chemical Sciences, University of Western Australia, Crawley, 6009, Australia,bMerck Research Laboratories, Rahway, New Jersey, USA, and cInternational Union of Crystallography, 5 Abbey Square, Chester CH1 2HU, England |
The data items in this category are as follows:
![[Scheme scheme41]](/schemes/Gach3o2scheme41.gif)
This category records information that applies collectively to the atom sites of the structural model. At present, the topics covered are the transformation matrix between Cartesian and cell fractional coordinates, and the methods used to locate the initial atom sites. _atom_sites_solution_primary describes how the first atom sites were determined, _atom_sites_solution_secondary describes how the remaining non-hydrogen sites were located and _atom_sites_solution_hydrogens describes how hydrogen atoms were located. The codes that are allowed for each of these refer to distinct solution methods, and at present only the seven formal values listed below are provided (although other values might be added in the future):
difmap difference-electron-density map;
vecmap real-space vector search;
heavy heavy-atom method;
direct structure-invariant direct methods;
geom inferred from neighbouring sites;
disper anomalous-dispersion techniques;
isomor isomorphous structure methods.
