Some applications of pulse radiolysis

The radiation chemistry of water is well understood and can be routinely used as a means of generating and studying unstable species — notably free readicals and metal ions in unusual oxidation states — in aqueous solution. The direct observation of the spectra and lifetime of such transient species makes possible the investigation of reaction mechanisms. Reactions of a great variety of organic and inorganic solutes have been studied, over time-scales down to nanoseconds. 

The behaviour of the hydrated electron is in general as expected for an electron surrounded by a small number of oriented water molecules. It behaves in many ways like a singly-charged anion of about the same size as the iodide ion. It is a powerful reducing agent, often acting by electron-addition (e - - A - A ). Rate constants vary from 16 s (for the reduction of water), up to 10 M s or more. The Arrhenius acti- 

From the mass of information (cf. Ref. [l,j,k]) a brief summary must suffice. Non-metallic free radicals are readily formed by oxidation of inorganic anions by the hydroxyl radical for example  

These radicals generally react by electron transfer, e.g.  

Aquo-metal ions in unusual oxidation states are readily produced by reduction of stable metallic ions by hydrated electrons e.g.  

---