Influence of radiation on reactivity and catalytic activity of solids
At the last syrnposiurn of this series, the fourth, there was for the first time a review of the effects of radiation upon the chernical reactivity of solidsl. The tirning was appropriate, since the field first began to show the effects of serious attention during the period between the third and fourth syrnposia. There had been sorne early suggestions and experiments2, but, naturally enough, the field lay dorrnant until radiation chernistry, solid state physics, and practical interest in radiation had reached reasonable stages of development. Now, four years later, there is more than enough material for a brief review, and there are radiation experirnents bearing on several kinds of reactivi ty. The basic idea in much of this work is that high-energy radiation can be used to introduce defects in a partly controllable way into solids, that these defects rnay influence various rnanifestations of reactivity, and that the altered reactivity can therefore be attributed to a specific entity in the solid. This attribution requires, of course, a knowledge of the defects produced, a knowledge sometimes available in advance, butsornetimes requiringfurther experimental study. It would be weil to rernark here that knowledge of physical radiation darnage is not so far ahead ofthat of reactivity that the flow of helpful information is unidirectional. Particularly with surfaces, conventional techniques do not provide wholly satisfactory inforrnation about defects, and we may anticipate mutually helpful interactions between adsorption, catalysis and other surface reactivity on the one hand, and radiation darnage on the other.