Radiation chemistry of nitrate ices

The yields of various products formed in γ-irradiated nitrate ices, viz NO2-, H2O2, O2 and H2, have been measured at different nitrate concentrations. Daniel's method of partition of yields has been employed to evaluate the direct and indirect effect contributions to the yields of the first three products. G(H2) is close to zero at all nitrate concentrations above approximately 0.5 mol dm-3. The mechanism of product formation has been discussed in the light of various reactions put forth to explain the radiolysis of fluid aqueous nitrate solutions. The effect of various scavengers for the primary species on the product yields has also been investigated. From this it is inferred that nitrate is able to scavenge both the reducing species, viz. H and e-sub(m) giving nitrite and possibly also the holes (h+sub(m)) giving O2, and excited water molecules (H2O*) giving H2O2 and additional nitrite. (author)