The evolution of newly formed species from the bombardments of H₂O:CO₂ ices by 52 MeV Ni as a function of fluence. a) Production of H₂O₂ from H₂O molecules in different ices. b) Production of CO, O₃, CO₃, and H₂CO₃ from CO₂ molecules in different ices. The relative abundance of each parental species is indicated. The lines indicate the fittings using Eq. (11), and the model parameters are given in Table 3.