The OH Yield in the Co60 γ Radiolysis of HNO3

The Co60 γ-ray radiolysis of concentrated aqueous solutions has been investigated and interpreted as the composite of two mechanisms, a molecular process HNO3→HNO3*→HNO2+12O2and a radical process HNO3→HNO3*→OH+NO2.Designation of these mechanisms as molecular and radical is a consequence of the products detected. The existence of these two decomposition mechanisms was gleaned from the determination of the G(H2), G(O2), GOH, G(Ce+3)No Tl+, and G(Ce+3)Tl+ and a comparison of these yields with those determined in comparable aqueous NaNO3 solutions. The GOH observed in HNO3 solutions was found to be directly proportional to the HNO3 concentration rather than a constant as was observed in comparable NaNO3 solutions. The radical process is appreciable, increasing from 0 at zero HNO3 concentration to 1.89 at 7 M HNO3. The data present for the first time evidence of a direct effect upon concentrated aqueous nitrate solutions that is directly proportional to nitrate concentration.