OQMD
The Open Quantum Materials Database (OQMD) is a database of DFT-calculated thermodynamic and structural properties of materials, developed by the Wolverton group at Northwestern University. Through ScholarMuse, an agent can find OQMD entries by chemical formula or by an exact set of elements and read formation energy, stability and structure data. The OQMD server is slow, so a lookup often takes a minute or more.
ScholarMuse tools: lookup_material. Each successful call uses credits.
Ask your agent
What your agent gets back
Every record carries id, source, title, url, license, attribution and retrievedAt. The fields below are the data that comes from OQMD.
lookup_material
Records whose source is oqmd. Values are DFT-computed. The lattice is the calculation cell, often the primitive cell.
- materialId
- OQMD entry id with an oqmd- prefix
- formula
- Composition name of the entry
- spacegroup
- Space group symbol
- prototype
- Structure prototype
- lattice
- a, b, c, angles and volume from the cell vectors
- cellSetting
- States that the cell is the calculation cell
- sites
- Number of atoms in the cell
- bandGapEv
- Computed band gap in eV
- formationEnergyPerAtomEv
- Formation energy in eV per atom
- energyAboveHullEv
- Distance above the convex hull, eV per atom
- isStable
- True when the entry is on the convex hull
- icsdId
- ICSD id, when the entry has one
What it covers
- OQMD formation-energy entries: DFT-computed formation energy, hull stability, band gap and structure summary.
- Search by formula, or by a list of 1 to 8 element symbols, which returns entries made of exactly those elements.
- Results are sorted by stability, most stable first. stable_only keeps entries on the convex hull.
Limits
- Slow. The OQMD server often answers late or with a temporary error. Each attempt may wait 30 seconds and there are up to 4 attempts, so a lookup often takes a minute or more.
- OQMD entries cannot be fetched by id. material_id accepts only Materials Project and COD ids, so search OQMD by formula or elements.
- At most 30 entries per call (default 10), shared with Materials Project and COD.
- Values are DFT-computed, not measured. No CIF file or atomic positions are returned.
How ScholarMuse reaches OQMD
The connector calls the OQMD REST API at oqmd.org/oqmdapi/formationenergy with a composition or an element-set filter, sorted by stability. No API key is sent.
Responses are cached for up to 7 days, so a repeated lookup is fast and changes at OQMD can take that long to appear.
API key: the upstream API can be called without one, so you do not add one.
Licence and attribution
Licence: CC BY 4.0
Data from the Open Quantum Materials Database (oqmd.org), CC BY 4.0. Cite: Saal et al., JOM 65, 1501 (2013); Kirklin et al., npj Comput. Mater. 1, 15010 (2015).
Records that come from OQMD carry this licence and attribution. When you cite the data in a paper, follow OQMD's own citation guidance.
