PAH survival time against collisions with CR ions, as a function of the fraction f of the transferred energy that goes into vibrational excitation. The lifetime has been calculated for PAHs of different sizes (N_C), assuming three values for the binding energy of the ejected fragment, E₀. The line style indicates the type of ion: dotted for H, dashed for He, solid for CNO and dot-dot-dashed for Fe-Co-Ni. The line color indicates the value of the fragment binding energy: gray for E₀ = 3.65 eV, black for E₀ = 4.58 eV and red for E₀ = 5.6 eV.