DISCUSSION 95 



the more methane was obtained. Since Eyring states the opposite to be true in 

 the gaseous state, I beUeve we have here an instance of the distinction that 

 Burton has discussed. 



Eyring: 



We are unable to explain this difference. Certain differences in reaction in 

 the liquid and gaseous states are due to the cage effect and to the fact that the 

 energy has not time to migrate when the irradiation is carried out in the gaseous 

 phase. In the gas the molecule may fly apart when it is hit by the bombarding 

 particle, whereas in the liquid state there is time for some of the energy to be 

 degraded into heat. 



Burton: 



The products of irradiation of both liquid and gaseous organic compounds are 

 characterized by their complexity, but there is some indication, as Eyring sug- 

 gests, of a smaller diversity of products in the liquid phase. 



Allen : 



Previous talks might give the impression that radiation chemistry is such a 

 hopelessly complicated subject as to be of little use to radiobiologists. However, 

 experiments in radiation chemistry frequently give reaction rate daws which 

 appear to be reasonably simple and rational. In solution, especially, the ob- 

 served phenomena can be correlated in a sensible fashion and certain valid 

 predictions made. As in other fields of chemistry, a good deal can be understood 

 about reactions without attempting to ascertain the complete details of the 

 molecular dynamics of each reaction. In radiation chemistry, the attempt to 

 discuss in full detail the nature of all the types of activation, though of interest 

 to radiation chemists, may well tend to give other people too pessimistic an 

 impression of the values and possibilities of this field of study. 



Burton (Communicated) : 



The techniques, disciphnes, and speculations of radiation chemistry are similar 

 to those of other branches of chemistry. Efforts toward detailed understanding 

 are common to all branches of science, and the existence and relation of such 

 efforts should prove a source of encouragement to those not actively engaged in 

 the field. Such efforts are in the direction of simplification and unification. 

 Detailed understanding and well-developed theory Hmit the number of facts 

 which must be remembered and indeed make a subject more attractive to the 

 uninitiate. 



Platzman : 



If chemical reactions — thermal, photochemical, or radiation-chemical — seem 

 to be simpler in the liquid than in the gaseous phase (a debatable impression), 

 it is probably because we know so much less about them that we have inadequate 

 empirical or theoretical information about their complexities. 



