ELECTRON-ENERGY LOSS SPECTRA OF POLYCYCLIC AROMATIC-HYDROCARBONS

Polycyclic aromatic hydrocarbons (PAHs) have been tentatively identified as the source of infrared emission bands seen in reflection nebulae and other astronomical objects. PAHs may also play a role in other astronomical phenomena, but concrete identification of these systems await further understanding of the properties of PAHs as a class of molecules. We report on a survey of the electron energy loss spectroscopy of gas phase PAH molecules consisting of up to seven rings where we have limited the study to the more thermodynamically stable pericondensed systems. The aim of this work is to obtain absorption profiles (proportional to the oscillator strengths) from the visible to the soft X-ray region near 30 eV.