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International
Tables for Crystallography Volume E Subperiodic groups Edited by V. Kopský and D. B. Litvin © International Union of Crystallography 2006 |
International Tables for Crystallography (2006). Vol. E. ch. 5.2, p. 396
Section 5.2.2.4. The types of scanning
a
Department of Physics, University of the South Pacific, Suva, Fiji, and Institute of Physics, The Academy of Sciences of the Czech Republic, Na Slovance 2, PO Box 24, 180 40 Prague 8, Czech Republic, and bDepartment of Physics, Penn State Berks Campus, The Pennsylvania State University, PO Box 7009, Reading, PA 19610–6009, USA |
It is useful to characterize various scanning tasks using the names of the crystallographic systems of the scanned group and of the scanning group. The scanning tables are naturally built up from lower to higher symmetries, according to the standard sequence of space groups. In this process, some already-considered space groups of lower crystallographic systems appear as scanning groups for those orientations which are not invariant under the point group G of the scanned space group ![[\cal G]](/teximages/acch1o3/acch1o3fi832.svg)
of a higher crystallographic system. In the first column of Table 5.2.2.1![[link]](/graphics/greenarr.gif)
, the crystallographic systems are listed in their usual hierarchy and to the right of each system are listed the lower systems from which some groups appear as scanning groups. We use terms such as tetragonal/monoclinic scanning when a tetragonal space group is considered and the scanning group ![[\cal H]](/teximages/a1apre9/a1apre9fi33.svg)
is monoclinic. Simple expressions such as orthorhombic scanning will mean that the scanning group is orthorhombic, to distinguish it from the expression scanning of orthorhombic groups, which means that the original space group is orthorhombic. The lattice of trigonal scanning groups in the case of cubic/trigonal scanning is always rhombohedral as indicated in parentheses.
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