Introduction to twinning.

By Simon Parsons. 2003

112 citations recorded by the source corpus.

A twinned crystal is an aggregate in which different domains are joined together according to a specific symmetry operation: the twin law. The diffraction patterns derived from different domains are rotated, reflected or inverted with respect to each other, depending on the nature of the relationship between the different domains, and weighted according to the quantity of a particular domain present in the crystal. The diffraction pattern measured during data collection is a superposition of all of these. Reflections from different domains may overlap and twinned crystals fall broadly into two categories in which either all reflections or only certain zones of reflections are affected by overlap. The former occurs when a crystal lattice belongs to a higher point group than the crystal structure itself; the latter frequently occurs when the twin law is a symmetry operation belonging to a higher symmetry supercell.

Subfields: Electronic, Optical and Magnetic Materials, Materials Chemistry, Physical and Theoretical Chemistry

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In Electronic, Optical and Magnetic Materials

1. Pavel V. Afonine
2. Alexandre Urzhumtsev
3. Paul D. Adams
4. Petrus H. Zwart
5. J. Helliwell

In Materials Chemistry

1. Paul D. Adams
2. Pavel V. Afonine
3. T. C. Terwilliger
4. Nigel W. Moriarty
5. Randy J. Read
6. Alexandre Urzhumtsev
7. Nathaniel Echols
8. Jane S. Richardson

In Physical and Theoretical Chemistry

1. Pavel V. Afonine
2. Alexandre Urzhumtsev
3. Paul D. Adams
4. R. Grosse-Kunstleve
5. Randy J. Read
6. Petrus H. Zwart
7. T. C. Terwilliger
8. J. Helliwell

Citations in the corpus

• Towards automated crystallographic structure refinement with phenix.refine (2012, methodology): “If twinning (for a review, see Parsons, 2003; Helliwell, 2008) is suspected, a user can run phenix.xtriage (Zwart et al., 2005) to obtain a twin-law operator to be used by the twin-refinement target in phenix.refine.”
• Data processing and analysis with the autoPROC toolbox (2011, unknown): “These could be a consequence of split crystals, of a satellite crystal being present in the loop or of a specific relation between domains, i.e. nonmerohedral twinning (for a recent review on twinning, see Parsons, 2003).”
• Macromolecular crystal twinning, lattice disorders and multiple crystals (2008, background): “A very clear description and introduction to twinning is given by Parsons (20).”
• A New Generation of Crystallographic Validation Tools for the Protein Data Bank (2011, background): “In certain cases, some of them pathological, these intensity distributions are perturbed; for example,merohedraltwinningleadstochangedintensitydistribu-tionsandmustbeaccountedforappropriatelyinstructuresolution (see Parsons, 2003 for a review of twinning phenomena).”