The NASA Ames PAH IR Spectroscopic Database: PAH Spectroscopy at Your Fingertips

Grant #: NNX11AG11G
Senior Scientist: Alessandra Ricca

Observations by the Spitzer Space Telescope and the Infrared Space Observatory show that the emission bands formerly referred to as the Unidentified Infrared Emission Features (UIRs) dominate the mid-IR of almost all astronomical sources. It is now time to go beyond simply labeling the IR emission bands and exploit them as new probes of the Solar System and the Universe.

Our current database ( contains 700 computational and 75 infrared experimental spectra of PAH molecules. Users can now import their astronomical spectra and fit them to our computed spectra using a non-negative least-square fit approach. This opens up the interpretation of observations from ongoing and future IR missions. In this study we plan to expand the database by adding the spectra of more complex systems, such as PAH clusters, carbon nanograins and PAHs in ices. We will also add more tools to help interpret the data.