httk property definitionsProperty definitions using the OPTIMADE property definition format, hosted by httk
This page documents an OPTIMADE Property Definition. See https://schemas.optimade.org/ for more information.
ID: https://schemas.httk.org/defs/v0.1/properties/structure/radial_distribution_function
Definition name: radial_distribution_function
Property name: Radial distribution function
Description: Radial distribution function g(r) of a structure or trajectory, binned in distance.
Type: dictionary
Implementation requirements:
- Support: OPTIONAL support in implementations, i.e., MAY be null.
Requirements/Conventions:
bin_edges (angstrom, dimension _httk_dim_radial_bin_edges) are the bin edges; its length is the number of bins plus one.g (dimensionless, dimension _httk_dim_radial_bins) is the value of each bin between consecutive edges.pair (optional, a list of two strings over _httk_dim_species_pair) gives the ordered central and neighbour species; it is absent for the total radial distribution function.A null value means the quantity is not available or not recorded.
Examples:
JSON definition:
{
"$id": "https://schemas.httk.org/defs/v0.1/properties/structure/radial_distribution_function",
"$schema": "https://schemas.optimade.org/meta/v1.3/optimade/property_definition.json",
"title": "Radial distribution function",
"x-optimade-type": "dictionary",
"x-optimade-definition": {
"kind": "property",
"version": "0.1.0",
"format": "1.3",
"name": "radial_distribution_function",
"label": "radial_distribution_function_structure_httk"
},
"x-optimade-unit": "inapplicable",
"x-optimade-unit-definitions": [
{
"$id": "https://schemas.optimade.org/defs/v1.2/units/si/general/angstrom",
"title": "\u00e5ngstr\u00f6m",
"symbol": "angstrom",
"display-symbol": "\u00c5",
"description": "A unit of length equal to 10\u207b\u00b9\u2070 meter, using the current, or one of the historical, definitions of the SI units.\n\nThe \u00e5ngstr\u00f6m unit appears in the International System of Units (SI), 1st ed. (1970) defined as \"1 \u00c5 = 0.1 nm = 10\u207b\u00b9\u2070 m\".\n\nThe \u00e5ngstr\u00f6m unit was implicitly redefined via the redefinition of the metre at the 17th CGPM meeting (1983), resolution 1.\n\n- The International System of Units (SI), 1st ed. (1970) categorizes the unit as \"temporarily admitted\" for use with the SI units.\n- The International System of Units (SI), 7th ed. (1998) changes the categorization to \"Other non-SI units currently accepted for use with the International System.\"\n- The International System of Units (SI), 8th ed. (2006) changes the categorization to \"Other non-SI units\" and adds as a clarifying footnote \"The \u00e5ngstr\u00f6m is widely used by x-ray crystallographers and structural chemists because all chemical bonds lie in the range 1 to 3 \u00e5ngstr\u00f6ms. However it has no official sanction from the CIPM or the CGPM.\"\n- The \u00e5ngstr\u00f6m is omitted in the International System of Units (SI), 9th Edition (2019).\n\nThis is a generalized definition taken to reference the current, or one of the historical, SI unit definitions.\nThis definition is intended for situations when it is not possible to be more precise, e.g., in contexts where data have been collected that uses different historical SI definitions.",
"compatibility": [
"https://schemas.optimade.org/defs/v1.2/units/si/1970/temporary/angstrom",
"https://schemas.optimade.org/defs/v1.2/units/si/1983/temporary/angstrom"
],
"resources": [
{
"relation": "Definition in the International System of Units (SI), 1st Edition",
"resource-id": "https://www.bipm.org/en/publications/si-brochure"
},
{
"relation": "Redefinition of the metre at the 17th CGPM meeting (1983), resolution 1",
"resource-id": "https://www.bipm.org/en/committees/cg/cgpm/17-1983/resolution-1"
},
{
"relation": "Wikipedia article describing the unit",
"resource-id": "https://en.wikipedia.org/wiki/Angstrom"
}
],
"defining-relation": {
"base-units": [
{
"symbol": "m",
"id": "https://schemas.optimade.org/defs/v1.2/units/si/general/metre"
}
],
"base-units-expression": "m",
"scale": {
"exponent": -10
}
},
"x-optimade-definition": {
"label": "angstrom_si_general",
"kind": "unit",
"format": "1.2",
"version": "1.2.0",
"name": "angstrom"
}
}
],
"x-optimade-requirements": {
"support": "may",
"sortable": false,
"query-support": "none"
},
"type": [
"object",
"null"
],
"required": [
"bin_edges",
"g"
],
"description": "Radial distribution function g(r) of a structure or trajectory, binned in distance.\n\n**Requirements/Conventions**:\n\n- `bin_edges` (angstrom, dimension `_httk_dim_radial_bin_edges`) are the bin edges; its length is the number of bins plus one.\n- `g` (dimensionless, dimension `_httk_dim_radial_bins`) is the value of each bin between consecutive edges.\n- `pair` (optional, a list of two strings over `_httk_dim_species_pair`) gives the ordered central and neighbour species; it is absent for the total radial distribution function.\n- Normalization: directed pair counts excluding self pairs, divided by the ideal-gas expectation N_A (N_B - delta_AB)/V and the shell volume; g is the ratio of the frame-summed counts to the frame-summed ideal-gas expectations, which differs from the mean of per-frame g when N or V vary between frames.\n\nA null value means the quantity is not available or not recorded.",
"properties": {
"bin_edges": {
"x-optimade-type": "list",
"x-optimade-unit": "inapplicable",
"x-optimade-dimensions": {
"names": [
"_httk_dim_radial_bin_edges"
],
"sizes": [
null
]
},
"type": [
"array"
],
"items": {
"x-optimade-type": "float",
"x-optimade-unit": "angstrom",
"type": [
"number"
]
}
},
"g": {
"x-optimade-type": "list",
"x-optimade-unit": "inapplicable",
"x-optimade-dimensions": {
"names": [
"_httk_dim_radial_bins"
],
"sizes": [
null
]
},
"type": [
"array"
],
"items": {
"x-optimade-type": "float",
"x-optimade-unit": "dimensionless",
"type": [
"number"
]
}
},
"pair": {
"x-optimade-type": "list",
"x-optimade-unit": "inapplicable",
"x-optimade-dimensions": {
"names": [
"_httk_dim_species_pair"
],
"sizes": [
2
]
},
"type": [
"array"
],
"items": {
"x-optimade-type": "string",
"x-optimade-unit": "inapplicable",
"type": [
"string"
]
}
}
}
}