PAHdb and OCdb are open access datasets and tools owned and maintained by NASA. They are available to assist in analyzing JWST observations and developing JWST proposals. Feedback and questions about these tools should be submitted directly to them*.

The NASA Ames PAH IR Spectroscopic Database (PAHdb)

The NASA Ames Polycyclic Aromatic Hydrocarbon (PAH) Infrared (IR) Spectroscopic Database (PAHdb) provides from-the-ground-up means to analyze and interpret the PAH component in JWST observations. It offers the spectroscopic data (both laboratory-measured and quantum-chemically computed) of PAHs, advanced molecular excitation/emission models, ready-to-use software tools, and the comprehensive documentation needed for astrophysical/chemical modeling and/or direct spectral fitting.

Website

The PAHdb website allows perusal of available PAH data, download options, and online analysis tools. It also provides extensive help, including links to PAHdb-related instructional videos.

PAHdb website

Software Tools

The three software tools — the AmesPAHdbIDLSuite, AmesPAHdbPythonSuite, and pyPAHdb — can be obtained from PAHdb’s GitHub repositories.

Documentation

Extensive documentation covering all aspects of PAHdb are available via its Documentation Portal.

JWebbinars

Two JWebbinars have been held to teach the JWST community how to utilize the database and available tools:

• PDRs4All Early Release Science program (ID 1288) JWebbinar was held in December 2022 and demonstrated the pyPAHdb tool to analyze and interpret JWST observations.
• JWST and the NASA Ames PAH IR Spectroscopic Database JWebbinar was held in June 2025 and demonstrated how to search the database, utilize the online tools for simple analyses, download data, and use the PAHdb Python suite of models and tools to analyze and interpret JWST observations.

Videos and materials from these two JWebbinars are available on the JWebbinar page. 

The Optical Constants Database (OCdb)

The Optical Constants database (OCdb) is a data repository developed to provide published, peer-reviewed, optical constants of materials relevant to planetary and astrophysical environments to the scientific community for the analysis and interpretation of observational data.

Optical constants are the real and imaginary parts of the complex refractive index, n + ik, of a material, which describe how a material interacts with incident light (transmission, reflection, refraction, absorption, scattering). They are fundamental input parameters for models (e.g. radiative transfer, atmospheric, and reflectance spectral models) that are used to interpret observational data.

The goal of the Optical Constants database is to centralize published optical constants data to facilitate their access by the community. We therefore encourage laboratories generating optical constants to contribute their data in order to increase their visibility and availability.

Website

The OCdb website allows searching for and downloading optical constants data.

OCdb website