RAMAN-SPECTRA OF DIFFERENT CARBONACEOUS MATERIALS OF ASTROPHYSICAL INTEREST

We present here the Raman spectra of 9 different carbonaceous materials of astronomical relevance, including single polycyclic aromatic hydrocarbons and mixtures. Eight of 9 samples show two main bands falling respectively at around 1600 and 1350 cm-1 which imply that all the materials are composed by randomly oriented structural units varying from 50 to 80 Å in size. Further bands and/or shoulders appear in some cases between 800 and 1700 cm-1 (6 and 12 μm) and are attributed to CC or CHn (n = 1,2,3) functional groups. The coronene spectrum is the only one which does not present any significant band although it shows a very high level of fluorescence. These results provide information about candidate materials which may account for unidentified IR bands observed in astronomical sources. © 1990.