['For', 'Xe', 'diffusion', 'in', 'UO2−x', ',', 'UO2', 'and', 'UO2+x', 'the', 'activation', 'energies', 'calculated', 'using', 'DFT', 'are', '7.04–12.92', '\xa0', 'eV', ',', '4.15–7.88', '\xa0', 'eV', 'and', '1.38–4.07', '\xa0', 'eV', 'with', 'the', 'ranges', 'reflecting', 'the', 'way', 'the', 'calculations', 'were', 'performed', 'depending', 'on', 'the', 'charge', 'states', 'of', 'the', 'defects', 'involved', 'and', 'the', 'presence', 'of', 'a', 'Jahn', '–', 'Teller', 'distortion', '[', '7', ']', '.']