mat-db-nist-janaf

Goal

To query experimental temperature-dependent thermodynamic properties and standard states (e.g. Standard Enthalpy of Formation $\Delta_f H^\circ_{298}$, Standard Entropy $S^\circ_{298}$, and $C_p$) from the NIST Chemistry WebBook and JANAF tables for benchmarking against DFT/MLIP calculations.

Instructions

Step 1. Query Thermochemistry Data

Use the query_janaf.py script to fetch thermodynamic data for a given chemical formula. The script automatically searches the WebBook for the closest matching standard element or compound and parses the HTML tables to extract the gas-phase or condensed-phase standard thermochemistry values.

# Env: base-agent
python .agents/skills/mat-db-nist-janaf/scripts/query_janaf.py <formula> <output_json>

Parameters:

• formula: The chemical formula to query (e.g., CH4, CO2, H2O).
• output_json: Path to the output JSON file where results will be stored.

Constraints

• Environments: The scripts require the base-agent Conda environment.
• Scraping Dependability: This script utilizes HTML scraping (beautifulsoup4). If the NIST WebBook layout changes in the future, the table selectors may need to be updated.
• Isotopes: By default, the script skips explicitly isotopically-labelled variants (unless it's the only match) to return the standard natural-abundance compound.

References

• Linstrom, P.J. and Mallard, W.G., Eds., NIST Chemistry WebBook, NIST Standard Reference Database Number 69, National Institute of Standards and Technology, Gaithersburg MD. URL
• Chase, M.W., Jr., NIST-JANAF Thermochemical Tables, Fourth Edition, J. Phys. Chem. Ref. Data, Monograph 9, 1998, 1-1951.

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Author: Bowen Deng Contact: GitHub @learningmatter-mit