Mapping the structural diversity of C60 carbon clusters and their infrared response

International audienceThe current debate about the nature of the carbonaceous material carrying the infrared (IR) emission spectra of planetary and proto-planetary nebulae, including the broad plateaus, calls for further studies on the interplay between structure and spectroscopy of carbon-based compounds of astrophysihlinecal interest. In this work, broad statistical samples of C 60 isomers were computationally determined without any bias using a reactive force field, their IR spectra being subsequently obtained following local optimization at the density functional based tight-binding level of theory. Structural analysis reveals four main structural families identified as cages, planar polycyclic aromatics, pretzels and branched. Comparison with available astronomical spectra indicates that only the cage family could contribute to the plateau observed in the 6-9 µm region. The present framework shows great promises to explore structural and spectroscopic features in more diverse and possibly hydrogenated carbonaceous compounds, in relation with astronomical observations