22 Atoms ROTATIONAL SPECTROSCOPY OF PAHs: ACENAPHTHENE, ACENAPHTHYLENE AND FLUORENE S. Thorwirth, P. Theule, C. A. Gottlieb, M. C. McCarthy, and P. Thaddeus Astrochemistry: Recent Successes and Current Challenges, IAU Symposium No. 231, 2005 link to abstract Rotational Spectra of Small PAHs: Acenaphthene, Acenaphthylene, Azulene, and Fluorene S. Thorwirth, P. Theule, C. A. Gottlieb, M. C. McCarthy, and P. Thaddeus The Astrophysical Journal, 662: 1309-1314, 2007 link to paper