.. auto-generated by dev_tools.docs.nxdl from the NXDL source contributed_definitions/NXunit_cell.nxdl.xml -- DO NOT EDIT .. index:: ! NXunit_cell (base class) ! unit_cell (base class) see: unit_cell (base class); NXunit_cell .. _NXunit_cell: =========== NXunit_cell =========== **Status**: base class, extends :ref:`NXobject` **Description**: .. collapse:: Description of a unit cell, i.e., the crystal structure of a single ... Description of a unit cell, i.e., the crystal structure of a single thermodynamic phase. **Symbols**: **n_pos**: Number of atom positions. **Groups cited**: none **Structure**: .. _/NXunit_cell/crystallographic_database_identifier-field: .. index:: crystallographic_database_identifier (field) **crystallographic_database_identifier**: (optional) :ref:`NX_CHAR ` .. collapse:: Identifier of an entry resolvable via crystallographic_database ... Identifier of an entry resolvable via crystallographic_database which was used for creating this structure model. .. _/NXunit_cell/crystallographic_database-field: .. index:: crystallographic_database (field) **crystallographic_database**: (optional) :ref:`NX_CHAR ` .. collapse:: Name of the crystallographic database to resolve ... Name of the crystallographic database to resolve crystallographic_database_identifier e.g. COD, ICSD, or others. .. _/NXunit_cell/lattice_system-field: .. index:: lattice_system (field) **lattice_system**: (optional) :ref:`NX_CHAR ` .. collapse:: A lattice system is a group of lattices with the same set of lattice point gro ... A lattice system is a group of lattices with the same set of lattice point groups. For further information, see https://en.wikipedia.org/wiki/Crystal_system. Any of these values: * ``triclinic`` * ``monoclinic`` * ``orthorhombic`` * ``tetragonal`` * ``rhombohedral`` * ``hexagonal`` * ``cubic`` .. _/NXunit_cell/space_group-field: .. index:: space_group (field) **space_group**: (optional) :ref:`NX_CHAR ` .. collapse:: Crystallographic space group. ... Crystallographic space group. A space group is the symmetry group of a repeating pattern in space. For further information, see International Table for Crystallography (https://it.iucr.org/). .. _/NXunit_cell/point_group-field: .. index:: point_group (field) **point_group**: (optional) :ref:`NX_CHAR ` .. collapse:: Crystallographic point group. ... Crystallographic point group. A crystallographic point group is a set of symmetry operations, corresponding to one of the point groups in three dimensions, such that each operation (perhaps followed by a translation) would leave the structure of a crystal unchanged. This field should use Schoenflies notation (see Schoenflies, A., Krystallsysteme und Krystallstructur, 1891). For further information, see https://dictionary.iucr.org/Point_group. .. _/NXunit_cell/laue_group-field: .. index:: laue_group (field) **laue_group**: (optional) :ref:`NX_CHAR ` .. collapse:: Laue group (also called Laue class). ... Laue group (also called Laue class). The Laue classes are eleven geometric crystal classes containing centrosymmetric crystallographic types of point groups and their subgroups. When absorption is negligible and Friedel's law applies, it is impossible to distinguish by diffraction between a centrosymmetric point group and one of its non-centrosymmetric subgroups; only point groups belonging to different Laue classes can then be distinguished. For further information, see https://dictionary.iucr.org/Laue_class. .. _/NXunit_cell/a_b_c-field: .. index:: a_b_c (field) **a_b_c**: (optional) :ref:`NX_FLOAT ` (Rank: 1, Dimensions: [3]) {units=\ :ref:`NX_LENGTH `} Crystallography unit cell parameters a, b, and c .. _/NXunit_cell/base_vector_a-field: .. index:: base_vector_a (field) **base_vector_a**: (optional) :ref:`NX_FLOAT ` (Rank: 1, Dimensions: [3]) {units=\ :ref:`NX_LENGTH `} Crystallography unit cell vector a .. _/NXunit_cell/base_vector_a@depends_on-attribute: .. index:: depends_on (field attribute) **@depends_on**: (optional) :ref:`NX_CHAR ` For definining which coordinate system the unit cell vector a is defined in. .. _/NXunit_cell/base_vector_b-field: .. index:: base_vector_b (field) **base_vector_b**: (optional) :ref:`NX_FLOAT ` (Rank: 1, Dimensions: [3]) {units=\ :ref:`NX_LENGTH `} Crystallography unit cell vector b .. _/NXunit_cell/base_vector_b@depends_on-attribute: .. index:: depends_on (field attribute) **@depends_on**: (optional) :ref:`NX_CHAR ` For definining which coordinate system the unit cell vector b is defined in. .. _/NXunit_cell/base_vector_c-field: .. index:: base_vector_c (field) **base_vector_c**: (optional) :ref:`NX_FLOAT ` (Rank: 1, Dimensions: [3]) {units=\ :ref:`NX_LENGTH `} Crystallography unit cell vector c .. _/NXunit_cell/base_vector_c@depends_on-attribute: .. index:: depends_on (field attribute) **@depends_on**: (optional) :ref:`NX_CHAR ` For definining which coordinate system the unit cell vector c is defined in. .. _/NXunit_cell/alpha_beta_gamma-field: .. index:: alpha_beta_gamma (field) **alpha_beta_gamma**: (optional) :ref:`NX_FLOAT ` (Rank: 1, Dimensions: [3]) {units=\ :ref:`NX_ANGLE `} Crystallography unit cell angles alpha, beta, and gamma .. _/NXunit_cell/volume-field: .. index:: volume (field) **volume**: (optional) :ref:`NX_FLOAT ` {units=\ :ref:`NX_VOLUME `} Volume of the unit cell .. _/NXunit_cell/is_centrosymmetric-field: .. index:: is_centrosymmetric (field) **is_centrosymmetric**: (optional) :ref:`NX_BOOLEAN ` .. collapse:: True if space group is considered a centrosymmetric one. ... True if space group is considered a centrosymmetric one. False if space group is considered a non-centrosymmetric one. Centrosymmetric has all types and combinations of symmetry elements (translation, rotational axis, mirror planes, center of inversion) Non-centrosymmetric compared to centrosymmetric is constrained (no inversion). Chiral compared to non-centrosymmetric is constrained (no mirror planes). .. _/NXunit_cell/is_chiral-field: .. index:: is_chiral (field) **is_chiral**: (optional) :ref:`NX_BOOLEAN ` .. collapse:: True if space group is considered a chiral one. ... True if space group is considered a chiral one. False if space group is consider a non-chiral one. .. _/NXunit_cell/phase_identifier-field: .. index:: phase_identifier (field) **phase_identifier**: (optional) :ref:`NX_UINT ` {units=\ :ref:`NX_UNITLESS `} .. collapse:: Identifier for the phase. ... Identifier for the phase. The value 0 is reserved for the unknown phase which represents the null-model that no phase model was sufficiently significantly confirmed. .. _/NXunit_cell/phase_name-field: .. index:: phase_name (field) **phase_name**: (optional) :ref:`NX_CHAR ` Trivial name of the phase/alias. .. _/NXunit_cell/atom_identifier-field: .. index:: atom_identifier (field) **atom_identifier**: (optional) :ref:`NX_CHAR ` (Rank: 1, Dimensions: [n_pos]) Labels for each atom position .. _/NXunit_cell/atom-field: .. index:: atom (field) **atom**: (optional) :ref:`NX_UINT ` (Rank: 1, Dimensions: [n_pos]) {units=\ :ref:`NX_UNITLESS `} .. collapse:: The hash value :math:`H` is :math:`H = Z + N \cdot 256` with :math:`Z` ... The hash value :math:`H` is :math:`H = Z + N \cdot 256` with :math:`Z` the number of protons and :math:`N` the number of neutrons of each isotope respectively. :math:`Z` and :math:`N` have to be 8-bit unsigned integers. For the rationale behind this `M. Kühbach et al. (2021) `_ .. _/NXunit_cell/atom_positions-field: .. index:: atom_positions (field) **atom_positions**: (optional) :ref:`NX_FLOAT ` (Rank: 2, Dimensions: [n_pos, 3]) {units=\ :ref:`NX_LENGTH `} Atom positions x, y, z. .. _/NXunit_cell/atom_positions@depends_on-attribute: .. index:: depends_on (field attribute) **@depends_on**: (optional) :ref:`NX_CHAR ` .. collapse:: Reference to an instance of NXcoordinate_system whereby the positions can be ... Reference to an instance of NXcoordinate_system whereby the positions can be resolved. .. _/NXunit_cell/atom_occupancy-field: .. index:: atom_occupancy (field) **atom_occupancy**: (optional) :ref:`NX_FLOAT ` (Rank: 1, Dimensions: [n_pos]) {units=\ :ref:`NX_DIMENSIONLESS `} Relative occupancy of the atom position. .. _/NXunit_cell/depends_on-field: .. index:: depends_on (field) **depends_on**: (optional) :ref:`NX_CHAR ` For definining which coordinate system the unit cell parameters are defined in. Hypertext Anchors ----------------- List of hypertext anchors for all groups, fields, attributes, and links defined in this class. * :ref:`/NXunit_cell/a_b_c-field ` * :ref:`/NXunit_cell/alpha_beta_gamma-field ` * :ref:`/NXunit_cell/atom-field ` * :ref:`/NXunit_cell/atom_identifier-field ` * :ref:`/NXunit_cell/atom_occupancy-field ` * :ref:`/NXunit_cell/atom_positions-field ` * :ref:`/NXunit_cell/atom_positions@depends_on-attribute ` * :ref:`/NXunit_cell/base_vector_a-field ` * :ref:`/NXunit_cell/base_vector_a@depends_on-attribute ` * :ref:`/NXunit_cell/base_vector_b-field ` * :ref:`/NXunit_cell/base_vector_b@depends_on-attribute ` * :ref:`/NXunit_cell/base_vector_c-field ` * :ref:`/NXunit_cell/base_vector_c@depends_on-attribute ` * :ref:`/NXunit_cell/crystallographic_database-field ` * :ref:`/NXunit_cell/crystallographic_database_identifier-field ` * :ref:`/NXunit_cell/depends_on-field ` * :ref:`/NXunit_cell/is_centrosymmetric-field ` * :ref:`/NXunit_cell/is_chiral-field ` * :ref:`/NXunit_cell/lattice_system-field ` * :ref:`/NXunit_cell/laue_group-field ` * :ref:`/NXunit_cell/phase_identifier-field ` * :ref:`/NXunit_cell/phase_name-field ` * :ref:`/NXunit_cell/point_group-field ` * :ref:`/NXunit_cell/space_group-field ` * :ref:`/NXunit_cell/volume-field ` **NXDL Source**: https://github.com/FAIRmat-NFDI/nexus_definitions/tree/fairmat/contributed_definitions/NXunit_cell.nxdl.xml