Primary Radical Yields in Pulse-Irradiated Alkaline Aqueous Solution

Relative primary radical yields of hydrated electrons, H atoms, and OH radicals were determined by measuring the amount of hydrated electron formed following a single 4-μsec pulse of X-rays. In neutral solution the amount of hydrated electron produced corresponds to $G({\rm e}_{{\rm aq}}^{-})$ , and at high pH's an additional amount is formed corresponding to G(H) by the reaction ${\rm H}+{\rm OH}^{-}={\rm H}_{2}{\rm O}+{\rm e}_{{\rm aq}}^{-}$ . In the presence of dissolved hydrogen the OH radical in yield G(OH) is also converted to hydrated electrons by reaction with hydrogen. The high optical absorption of the hydrated electron at 7000 A is used as a measure of its concentration. A pH range from 7 to 14.5 is covered. At pH above 12 the total radical yield, $G({\rm e}_{{\rm aq}}^{-})+G({\rm H})+G({\rm OH})$ , is constant, as is the total reducing yield, $G({\rm e}_{{\rm aq}}^{-})+G({\rm H})$ . These relative yields are placed...