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.