Dr. Aigen Li of the University of Missouri-Columbia will investigate the photo-excitation and destruction of specific polycyclic aromatic hydrocarbon (PAH) molecules in (1) circumstellar dust disks, and (2) the interstellar medium of the Milky Way Galaxy, low metallicity galaxies, and active galactic nuclei (AGNs). In contrast to most previous modeling efforts which focus on ""astro-PAHs"" (which do not represent any specific material, but approximate the actual absorption properties of the PAH mixture in astrophysical regions), this project, taking a statistical-mechanical approach, will study 21 specific PAH molecules and their ions, ranging from naphthalene C10H8 to circumcoronene C54H18. This work will complement the PI''s two recent Spitzer Theory Programs which aim at the photophysics of astro-PAHs in dust disks, low metallicity galaxies, and AGNs.
The major outcomes of this research - (1) the emission spectra calculated for 21 specific PAH molecules and their ions in dust disks and in the interstellar medium of the Milky Way and external galaxies, and (2) the destruction rates of these 21 specific PAHs by ultraviolet and X-ray photons in various astrophysical environments - will be made available to the community, and will be useful for a broad range of scientific studies. This research will also have a positive impact on training graduate students and on developing an astronomy program at the University of Missouri-Columbia.
