Radiation chemistry of liquids

The areas where the use of the track model has been found particularly expedient are (1) LET variation of product yields in the radiation chemistry of liquids (2) the yield of escaped ions and its variation with particle LET (3) energy loss in primary excitations and ionizations (4) radiation-induced luminescence and (5) particle identification. 

The Radiation Chemistry of Liquid Water Principles and Applications... 

Photochemistry and Radiation Chemistry of Liquid Alkanes Formation and Decay of Low-Energy Excited States... 

However, it was subsequently shown9 that these observations could be more satisfactorily accounted for by the occurrence of free radical chain reactions. The free radicals might arise from ionic or excited species. The radiation chemistry of liquid water was claimed to be explicable10 in terms of the reactions of the hydrogen atom and the hydroxyl free radical. Ionic mechanisms consequently fell into disrepute, but it is interesting that in recent years ionic processes have been recognised as of increasing importance. The wheel has indeed turned full circle ... 

In general, however, the effect of phase is much less marked than for ionic species and results for different phases will not be considered separately in this section. Since, in fact, more experiments have been carried out on the radiation chemistry of liquids than of gases or solids, most of the results discussed in this section refer to the liquid state. 

Following the realisation that the reactions of the hydrated electron played an important role in the radiation chemistry of liquid water it was not long before evidence was sought, and found, that the electron and the counter cation could be involved in chemical reactions in non-polar liquids before they underwent neutralisation. Scholes and Simic (1964(49)) showed that on irradiation of solutions of nitrous oxide in hydrocarbons nitrogen was formed in the dissociative attachment reaction analogous to reaction (6). Similarly, Buchanan and Williams (1966(50)) attributed the formation of HD in Y lrradiated solutions of C2H3OD in cyclohexane to the transfer of a... 

Concurrently with the view that reactions of electrons and positive ions play an important part in the radiation chemistry of liquids, it was being demonstrated, notably by Hamill(56) and his co-workers over the period 1962-1966, that charge trapping, migration and reaction were also important In the radiation chemistry of many solid systems, especially at low temperatures. As a result of these studies, >-irradiation of low temperature solids has become perhaps the most versatile method of studying the spectroscopic properties of radical anions and cations. 

It might be expected that after years of study, the radiation chemistry of liquid water and dilute aqueous solutions would have been thoroughly documented. However, many modern day applications take place under conditions far from ambient. In particular, in nuclear... 

In real-world applications, the importance of interfaces is hard to overestimate and three chapters are devoted to the effects of radiation at aqueous-solid boundaries. Jonsson focuses on applications within the nuclear industry where basic studies on radiation effects at water-metal interfaces have enabled a proposal for safe storage of spent nuclear fuel. Also with implications for the nuclear industry, Musat et al. document alterations in the radiation chemistry of liquid water confined on the nanoscale. Such nanoconfmed solutions are prevalent in the media proposed and indeed in use for waste storage. In another application, radiation chemistry has successfully been used to produce nanoscale objects such as metallic clusters and nanoparticles, an area summarized by Remita and Remita. 

One of the most important general features of the radiation chemistry of liquids is that so much energy is deposited by the ionizing radiations, excited or reactive molecules are formed in close proximity and are likely to react with one another. This situation is not encountered inphotochemistry except when lasers are used for excitation. 

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