Infrared spectra of a thin film of coronene (in blue) irradiated with a ⁴⁸Ca beam recorded at different fluences. Insert: evolution of the integrated optical depth of the C=C IR band at ~1315 cm⁻¹, normalised to the initial film prior to irradiation. The solid line is an exponential fit of the destruction cross-section (Eq. (6)) to the data and the dashed lines represent ±3σ with respect to the best fit.