Spitzer Space Telescope - Archive Research Proposal #40131


PAH Spectra for Everyone

Principal Investigator: Louis  Allamandola
           Institution: NASA Ames Research Center

     Technical Contact: Louis  Allamandola, NASA Ames Research Center

Co-Investigators: 
Charlie Bauschlicher, Jr., NASA Ames Research Center                  
Andrew Mattioda, NASA Ames Research Center                            

Science Category: ISM 
Dollars Approved: 40000 

Abstract:
The Ames Astrochemistry Laboratory now has PAH IR spectra of more than 220
laboratory measured and over 600 theoretically calculated IR spectra of
polycyclic aromatic hydrocarbons (PAHs) in a multitude of forms. The vast
majority of these spectra are not readily accessible to the public. We propose
to make the full collection of the Ames experimental and computational
collection of PAH IR spectra available to the entire Spitzer community and
accessible via the World Wide Web (WWW). The laboratory measured mid-IR spectral
collection includes over 220 neutral, cationic, and anionic PAHs, PAHs with
deuterium in place of hydrogen, PAHs containing oxygen, and PAHs containing
nitrogen (PANHs). The formulae of the PAHs in the experimental data collection
range from C10H8 to C50H22. Unfortunately, it is not possible to obtain physical
samples of all of the types of PAHs that are of astrophysical interest for
experimental study. We also have an extensive collection of accurate
computational spectra to fill in gaps in the experimentally available spectra.
Our theoretical PAH spectral collection includes very large PAHs, PAHs
containing 40 to 132 carbon atoms which are comparable to the size of the PAHs
thought to dominate the interstellar emission spectrum. Large PAHs might be
multiply charged and these are also represented in the theoretical database.
There is also observational evidence for PAH cations with nitrogen in the inner
rings (PANHs) and interest in the spectroscopy of aromatic species containing
oxygen and deuterium as well as PAH metal clusters. All of these types of PAHs
are represented in the Ames computational PAH IR spectroscopic collection. If
funded, we plan to make our entire inventory of the lab spectra available to the
Spitzer community within the next two years.