The radiation chemistry of aqueous solutions III. The isotope effect for polonium α-particles and tritium β-particles

Investigations similar to those described in parts I and II for ordinary water have been made on D2O. For tritium β-particles the derived yields are GD = 3.34 ± 0.03, GOD = 2.26 ± 0.1, GD2O2 = 0.815 ± 0.02, GD2 = 0.275 ± 0.085 and G-D2O = 3.89 ± 0.14. Observed yields G(Ce3+)T1+ = 7.50 ± 0.5, G(Fe3+)-O2 = 7.15 ± 0.15, G(D2)0.1N = 0.61 ± 0.02 and G(D2O2)O2i = 1.02 ± 0.1 are close to expected values. For polonium α-particles of 3.0 and 1.6 MeV energy respectively the yields are G(Fe3+) = 6.20 and 4.27, G(Ce3+) = 3.20 and 2.68, G(Ce3+)T1+ = 3.50 and 2.85, and hence GD + GDO2 = 1.35 and 0.71, GOD = 0.15 and 0.085, GD2O2 = 1.0 and 1.03; G(D2O2)O2 for 1.6 MeV α-particles is 1.24. The isotope effect thus extends up to the highest accessible l. e. t. and in fact increases slightly, which is to be expected if it is caused by a more widespread distribution of D as compared with H atoms. Striking confirmation of the more widespread distribution of D is afforded by the fact that in deaerated tritiated solutions almost 100% of the available D atoms react with ferrous ion under conditions where only 60% of the available H atoms react.