The photolysis of aqueous systems at 1849 A I. Solutions containing nitrous oxide

Yield-time curves have been obtained for the illumination with 1849 Å light of aqueous solutions of N2O and the effect on these of added methanol has been measured. The results indicate that: (i) the oxygen atom produced by photolysis of N2O is in a singlet state, 1S or 1D, and can insert into a water molecule forming hydrogen peroxide, a conclusion confirmed by use of N218O ; (ii) the H2O2 is attacked and decomposed to oxygen and water by H atoms and OH radicals produced in the photolysis of water; (iii) if ϕ(N2O + hv -> N2 + O) is unity, ϕ(H2O ->H + OH) = 0.30 ±0.3 and ϕ(CH3OH + hv -> CH2O + H2 or CH3O + H) = 0.46 ±0.05; (iv) if the linear extinction coefficient of H2O for 1849 Å light is 1.8 cm-1 that for D2O is 0.14 cm-1 and the molar extinction coefficient for N2O is 60 ± 8 M-1 cm-1; and (v) when two CH2OH radicals interact ca. 4 % form CH2O + CH3OH and 96 % form (CH2OH)2.