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/energetics/chemical_potential_region
Definition name: chemical_potential_region
Property name: Chemical potential region
Description: Linear constraints defining the allowed region of absolute per-atom chemical potentials mu_i of a host compound against competing phases.
Type: dictionary
Implementation requirements:
- Support: OPTIONAL support in implementations, i.e., MAY be null.
Lists elements, host_coefficients share the dimension _httk_dim_elements; competing_coefficients has dimensions _httk_dim_competing_phases then _httk_dim_elements; competing_energies has the dimension _httk_dim_competing_phases. They MUST have consistent lengths. The competing lists may be empty.
Requirements/Conventions:
elements are the element labels, sorted by code point, defining the order of the potential vector.host_coefficients (dimensionless) are the host stoichiometry n_i as supplied, in elements order; they may be fractional, with zero for elements absent from the host.host_energy (eV) is the host total energy on that stoichiometric basis.competing_coefficients (dimensionless) are the competing-phase stoichiometries c_ji, with zero for absent elements; competing_energies (eV) are the matching total energies E_j. Elemental reference phases are present only if supplied as competing phases.host_energy, and for each competing phase j, sum_i c_ji mu_i <= E_j; the mu_i are absolute per-atom chemical potentials in eV on the same total-energy scale as the energies.A null value means the quantity is not available or not recorded.
Examples:
JSON definition:
{
"$id": "https://schemas.httk.org/defs/v0.1/properties/energetics/chemical_potential_region",
"$schema": "https://schemas.optimade.org/meta/v1.3/optimade/property_definition.json",
"title": "Chemical potential region",
"x-optimade-type": "dictionary",
"x-optimade-definition": {
"kind": "property",
"version": "0.1.0",
"format": "1.3",
"name": "chemical_potential_region",
"label": "chemical_potential_region_energetics_httk"
},
"x-optimade-unit": "inapplicable",
"x-optimade-unit-definitions": [
{
"$id": "https://schemas.optimade.org/defs/v1.2/units/si/general/electronvolt",
"title": "electron volt",
"symbol": "eV",
"display-symbol": "eV",
"description": "A unit of energy that representing the kinetic energy acquired by an electron as it accelerates through a 1 volt potential difference in a vacuum using the current, or one of the historical, definitions given in the editions of the International System of Units (SI).\n\nThe electronvolt unit appears in the International System of Units (SI), 1st ed. (1970) defined as \"1 electronvolt is the energy acquired by an electron after traversing a potential difference of 1 V in a vacuum; 1 eV = 1.60219\u00d710\u207b\u00b9\u2079 J approximately.\"\nThis definition makes the unit equal to 1 volt times the value of the elementary charge.\nIn the 2019 redefinition of the SI units the elementary charge is exactly 1.602176634\u00b710\u207b\u00b9\u2079 C, making the electron volt exactly equal to 1.602176634\u00b710\u207b\u00b9\u2079 J.\nThe International System of Units (SI), 9th ed. (2019) accordingly notes the exact relationship with the SI 2019 derived unit joule as \"1 eV = 1.602176634\u00b710\u207b\u00b9\u2079 J\" but retains the definition from 1970 in a footnote.\n\nThe unit is categorized in the International System of Units (SI), 9th ed. (2019) as \"Non-SI units accepted for use with the SI units\".\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/accepted/electronvolt",
"https://schemas.optimade.org/defs/v1.2/units/si/1983/accepted/electronvolt",
"https://schemas.optimade.org/defs/v1.2/units/si/2019/accepted/electronvolt"
],
"resources": [
{
"relation": "Definition in the International System of Units (SI), 9th Edition",
"resource-id": "https://www.bipm.org/en/publications/si-brochure"
},
{
"relation": "Wikipedia article describing the unit",
"resource-id": "https://en.wikipedia.org/wiki/Electronvolt"
}
],
"approximate-relations": [
{
"base-units": [
{
"symbol": "V",
"id": "https://schemas.optimade.org/defs/v1.2/units/si/general/volt"
},
{
"symbol": "e",
"id": "https://schemas.optimade.org/defs/v1.2/constants/codata/2018/electromagnetic/elementarycharge"
}
],
"base-units-expression": "e*V"
}
],
"x-optimade-definition": {
"label": "electronvolt_si_general",
"kind": "unit",
"format": "1.2",
"version": "1.2.0",
"name": "electronvolt"
}
}
],
"x-optimade-requirements": {
"support": "may",
"sortable": false,
"query-support": "none"
},
"type": [
"object",
"null"
],
"required": [
"elements",
"host_coefficients",
"host_energy",
"competing_coefficients",
"competing_energies"
],
"description": "Linear constraints defining the allowed region of absolute per-atom chemical potentials mu_i of a host compound against competing phases.\n\nLists `elements`, `host_coefficients` share the dimension `_httk_dim_elements`; `competing_coefficients` has dimensions `_httk_dim_competing_phases` then `_httk_dim_elements`; `competing_energies` has the dimension `_httk_dim_competing_phases`. They MUST have consistent lengths. The competing lists may be empty.\n\n**Requirements/Conventions**:\n\n- `elements` are the element labels, sorted by code point, defining the order of the potential vector.\n- `host_coefficients` (dimensionless) are the host stoichiometry n_i as supplied, in `elements` order; they may be fractional, with zero for elements absent from the host.\n- `host_energy` (eV) is the host total energy on that stoichiometric basis.\n- `competing_coefficients` (dimensionless) are the competing-phase stoichiometries c_ji, with zero for absent elements; `competing_energies` (eV) are the matching total energies E_j. Elemental reference phases are present only if supplied as competing phases.\n- The region is: sum_i n_i mu_i = `host_energy`, and for each competing phase j, sum_i c_ji mu_i <= E_j; the mu_i are absolute per-atom chemical potentials in eV on the same total-energy scale as the energies.\n\nA null value means the quantity is not available or not recorded.",
"properties": {
"elements": {
"x-optimade-type": "list",
"x-optimade-unit": "inapplicable",
"x-optimade-dimensions": {
"names": [
"_httk_dim_elements"
],
"sizes": [
null
]
},
"type": [
"array"
],
"items": {
"x-optimade-type": "string",
"x-optimade-unit": "inapplicable",
"type": [
"string"
]
}
},
"host_coefficients": {
"x-optimade-type": "list",
"x-optimade-unit": "inapplicable",
"x-optimade-dimensions": {
"names": [
"_httk_dim_elements"
],
"sizes": [
null
]
},
"type": [
"array"
],
"items": {
"x-optimade-type": "float",
"x-optimade-unit": "dimensionless",
"type": [
"number"
]
}
},
"host_energy": {
"x-optimade-type": "float",
"x-optimade-unit": "eV",
"type": [
"number"
]
},
"competing_coefficients": {
"x-optimade-type": "list",
"x-optimade-unit": "inapplicable",
"x-optimade-dimensions": {
"names": [
"_httk_dim_competing_phases"
],
"sizes": [
null
]
},
"type": [
"array"
],
"items": {
"x-optimade-type": "list",
"x-optimade-unit": "inapplicable",
"x-optimade-dimensions": {
"names": [
"_httk_dim_elements"
],
"sizes": [
null
]
},
"type": [
"array"
],
"items": {
"x-optimade-type": "float",
"x-optimade-unit": "dimensionless",
"type": [
"number"
]
}
}
},
"competing_energies": {
"x-optimade-type": "list",
"x-optimade-unit": "inapplicable",
"x-optimade-dimensions": {
"names": [
"_httk_dim_competing_phases"
],
"sizes": [
null
]
},
"type": [
"array"
],
"items": {
"x-optimade-type": "float",
"x-optimade-unit": "eV",
"type": [
"number"
]
}
}
}
}