Oxygen formation in gamma-ray irradiation of Fe2+ -Cu2+ solutions

The mechanism of O₂ formation has been studied in ⁶⁰ Co γ-ray-irradiated Fe(II) + Cu(II) solutions at 0.01 N HClO₄ and at 0.01, 0.08, and 0.80 N H₂ SO₄. In the H₂ SO₄ system, ${\rm G}({\rm O}_{2})$ rises to plateau levels near 0.02 as the ${\rm CuSO}_{4}/{\rm FeSO}_{4}$ ratio increases. The plateau value diminishes slightly and is displaced toward higher ${\rm CuSO}_{4}/{\rm FeSO}_{4}$ ratios with increasing acidity. The perchlorate system differs from the sulfate only at high ${\rm Cu}({\rm ClO}_{4})/{\rm Fe}({\rm ClO}_{4})_{2}$ ratios where $G({\rm O}_{2})$ rises to 0.10. The O₂ yield of 0.02 is not derived from "spur" HO₂, OH, H₂ O₂ or O₂, although the increase in $G({\rm O}_{2})$ above this level in the perchlorate system is attributed to H₂ O₂. "Spur" O atoms are postulated as the source of O₂ with the yield, $G({\rm O}_{2})$ = 0.02.