69 



uid like benzene, that there is any meaning in talking about ion pairs at all as 

 being the source of chemical effects. 



ALLEN: I think as to the meaning of ion pairs in liquids, it may mean 

 something in the context of a theory, but if you look at it operationally it is very 

 hard to imagine an experiment that could be directly related to this number. 

 From that viewpoint it seems to hold no significance. 



BURTON: There should be an operational difference. If what Dr. Platz- 

 man says is correct as compared with what Dr. Magee says, then these ions 

 are formed and are persistent so far from each other that there are effects 

 which should be detectible for H^O" 1 " dissociating into H + and OH, and solvated 

 electrons dissociating to give OH - and an H atom remotely. These phenomena 

 are so different that one might properly look for a suitable experiment by which 

 they can be differentiated. 



KAMEN: Let's be specific. What are these effects you are looking for? 



BURTON: You have to think of what kind of an experiment can be done to 

 find this. 



PLATZMAN: That is exactly the problem, and at the present time no one 

 is clever enough to think of an experiment that makes sense. 



KAMEN: The next thing I want to say is what difference does it actually 

 make to the radiation chemist as to whether this question is or isn't settled. Is 

 it really important? 



PLATZMAN: It might be a significant distinction. 



KAMEN: It is important to know what the radical pair is, what the the dis- 

 tribution is, and whether the mechanism of radical pair formation is through re- 

 combination of ions or through direct excitation. 



BURTON: The radical pair yield and the distribution of the radical pairs 

 are the important things, not the radical pair yield by itself. 



POLLARD: How do you know that radical pairs have any effect in biology? 

 The statement has been made that it is much more important to know the radi- 

 cal pair yield than the ion pair yield. 



KAMEN: Because that is experimentally something which you can meas- 

 ure. 



POLLARD: If only ion pairs have an effect in biology, one is not interest- 

 ed in radical pairs. 



KAMEN: There is some work by Read (19) purporting to show that the 

 electrostatic effect produced by the separation of the electron, say in protein 

 from its parent ion is such as could disrupt the molecule without intervention of 

 the radical reaction. 



BOAG: Read calculated that a radical electric field of the order of 10^ 

 volts/cm would be set up if two Gaussian charge distributions of opposite sign 

 and different half-widths were superimposed in accordance with the Jaffe 

 model. The region of high fiold is very small, however, and it seems un- 



