omnilab/oqmd API reference

Omnilab\Oqmd

OqmdSource class

final class OqmdSource extends HttpSource OqmdSource.php:30

The Open Quantum Materials Database (Northwestern University), DFT formation energies of some 700,000 materials, through its RESTful API (oqmd.org/oqmdapi): an entry by its OQMD id - its name (formula), space group, prototype, atoms and element types, volume, formation energy, distance to the convex hull, band gap, its ICSD id, the entry it duplicates -; the entries of a composition ("Al2O3") or a phase space ("Fe-O").

One call an entity or a page, no key. Not tested live: the service did not answer on 2026-10-15 (README).

const BASE_URI = 'https://oqmd.org/oqmdapi/'

const MAX_LIMIT = 100

The most entries a page holds.

const FIELDS = ['name', 'entry_id', 'icsd_id', 'duplicate_entry_id', 'composition_generic', 'prototype', 'spacegroup', 'natoms', 'ntypes', 'volume', 'delta_e', 'stability',…

The fields asked (the API's keywords).

OqmdSource::getName()

public function getName(): string

OqmdSource::capabilities()

public function capabilities(): array

OqmdSource::entity()

public function entity(Identifier|string $id): ?Entity

An entry by its OQMD id ("oqmd:6", its page; a bare number read as one); another base's identifier is refused before any call; null when OQMD has none.

OqmdSource::search()

public function search(Query $query): Page

The entries of a composition ("Al2O3") or a phase space ("Fe-O"), in OQMD's order; a domain other than chemistry answers nothing.

OqmdSourceFactory class

final class OqmdSourceFactory extends SourceFactory OqmdSourceFactory.php:20

The Open Quantum Materials Database: DFT formation energies, hull distances and band gaps of materials by OQMD id, composition or phase space - no key needed.

options: mailto: 'support@glitchr.io' # in the User-Agent throttle: 0 # seconds between two calls: no rate published base_uri: 'https://oqmd.org/oqmdapi/'

Options