diff --git a/schemas/src/defs/v1.2/properties/optimade/common/symmetry_operation_xyz.yaml b/schemas/src/defs/v1.2/properties/optimade/common/symmetry_operation_xyz.yaml new file mode 100644 index 000000000..57341624e --- /dev/null +++ b/schemas/src/defs/v1.2/properties/optimade/common/symmetry_operation_xyz.yaml @@ -0,0 +1,22 @@ +$$schema: "https://schemas.optimade.org/meta/v1.2/optimade/property_definition" +$id: "https://schemas.optimade.org/defs/v1.2/properties/optimade/common/symmetry_operation_xyz" +title: "Symmetry operation" +x-optimade-type: "string" +x-optimade-definition: + label: "symmetry_operation_xyz_optimade_common" + kind: "property" + version: "1.2.0" + format: "1.2" + name: "symmetry_operation_xyz" +description: |- + A symmetry operation given as general position x, y, z coordinates in algebraic form. + + **Requirements/Conventions:** + + - The symmetry operation is described by a string that gives that symmetry operation in Jones' faithful representation (Bradley & Cracknell, 1972: pp. 35-37), adapted for computer string notation. + - The letters `x`, `y` and `z` that are typesetted with overbars in printed text represent coordinate values multiplied by -1 and are encoded as `-x`, `-y` and `-z`, respectively. + - The syntax of the strings representing symmetry operations MUST conform to regular expressions given in appendix `The Symmetry Operation String Regular Expressions`_. +x-optimade-unit: inapplicable +type: + - "string" +maxLength: 3 diff --git a/schemas/src/defs/v1.2/properties/optimade/structures/space_group_symmetry_operations_xyz.yaml b/schemas/src/defs/v1.2/properties/optimade/structures/space_group_symmetry_operations_xyz.yaml new file mode 100644 index 000000000..c3fe75d95 --- /dev/null +++ b/schemas/src/defs/v1.2/properties/optimade/structures/space_group_symmetry_operations_xyz.yaml @@ -0,0 +1,42 @@ +$$schema: "https://schemas.optimade.org/meta/v1.2/optimade/property_definition" +$id: "https://schemas.optimade.org/defs/v1.2/properties/optimade/structures/space_group_symmetry_operations_xyz" +title: "Space group symmetry operations" +x-optimade-type: "list" +x-optimade-definition: + label: "space_group_symmetry_operations_xyz_optimade_structures" + kind: "property" + version: "1.2.0" + format: "1.2" + name: "space_group_symmetry_operations_xyz" +type: + - "array" + - "null" +description: |- + A list of symmetry operations given as general position x, y and z coordinates in algebraic form. + + **Requirements/Conventions**: + + - Each symmetry operation is described by a string that gives that symmetry operation in Jones' faithful representation (Bradley & Cracknell, 1972: pp. 35-37), adapted for computer string notation. + - The letters `x`, `y` and `z` that are typesetted with overbars in printed text represent coordinate values multiplied by -1 and are encoded as `-x`, `-y` and `-z`, respectively. + - The syntax of the strings representing symmetry operations MUST conform to regular expressions given in appendix `The Symmetry Operation String Regular Expressions`_. + - The interpretation of the strings MUST follow the conventions of the IUCr CIF core dictionary (IUCr, 2023). + - In particular, this property MUST explicitly provide all symmetry operations needed to generate all the atoms in the unit cell from the atoms in the asymmetric unit, for the setting used. + - This symmetry operation set MUST always include the `x,y,z` identity operation. + - The symmetry operations are to be applied to fractional atom coordinates. + - In case only Cartesian coordinates are available, these Cartesian coordinates must be converted to fractional coordinates before the application of the provided symmetry operations. + - If the symmetry operation list is present, it MUST be compatible with other space group specifications (e.g. the ITC space group number, the Hall symbol, the Hermann-Mauguin symbol) if these are present. + + **Notes**: + + - The list of space group symmetry operations applies to the whole periodic array of atoms and together with the lattice translations given in the :property:`lattice\_vectors` property provides the necessary information to reconstruct all atom site positions of the periodic material. + - Thus, the symmetry operations described in this property are only applicable to material models with at least one periodic dimension. + - This property is not meant to represent arbitrary symmetries of molecules, non-periodic (finite) collections of atoms or non-crystallographic symmetry. + + **Bibliographic References** + + - Bradley, C. J. and Cracknell, A. P. (1972) The Mathematical Theory of Symmetry in Solids. Oxford, Clarendon Press (paperback edition 2010) 745 p. ISBN `978-0-19-958258-7 `__. + - IUCr (2023) Core dictionary (coreCIF) version 2.4.5; data name `\_space\_group\_symop\_operation\_xyz`. Available from: https://www.iucr.org/__data/iucr/cifdic_html/1/cif_core.dic/Ispace_group_symop_operation_xyz.html [Accessed 2023-06-18T16:46+03:00]. +examples: + - ["x,y,z", "-x,y,-z"] + - ["x,y,z", "-x,y,-z", "x+1/2,y+1/2,z", "-x+1/2,y+1/2,-z"] +x-optimade-unit: "unapplicable"