Raman and infrared spectra of polycyclic aromatic hydrocarbon molecules of possible astrophysical interest

A laboratory analysis is performed by means of Raman and IR spectroscopy on six polycyclic aromatic hydrocarbons (PAHs) which are among the most stable and the most abundant PAHs suggested as an important constituent of interstellar matter. The Raman spectrum of PAHs exhibits intense peaks around 1350 and 1600/cm, falling close to the two broad bands observed from interplanetary dust particles (IDPs). They are sharper, however, and therefore appear less appropriate to simulate the Raman spectra of IDPs than the spectra of amorphous carbons. The analysis of their IR spectra suggests that physical processes capable of altering the spectral properties of PAHs have to be invoked to obtain a better match with astronomical spectral.