62 



BURTON: That is a rather important point. About two years ago in 

 this conference we pointed out that in this forward reaction, it is only a 

 matter of convenience to make the assumption that FU and H 2 2 are formed 

 in equivalent amount. We felt at that time, and we know very definitely 

 now, that the yield of H2 in the forward reaction is not the same as that 

 of H2O2 in the forward reaction. 



MAGEE: The only trouble is I haven't seen any improvement that I 

 think I would like to discuss at this time. There are so many things to 

 consider. When you start to think about it you don't want to improve one 

 thing and leave something else just as important neglected. 



ALLEN: I think Dr. Burton's point is important. On this theory, out- 

 side of the details, the general picture is that these radicals are uniformly 

 distributed in a region from which they diffuse out, and it is hard to see 

 how this can give you anything very different from having the amount of hy- 

 drogen formed pretty close to the amount of peroxide formed. 



MAGEE: It will be about the same. 



ALLEN: The evidence is becoming increasingly clear that the peroxide 

 yield of gamma rays is about twice the yield of hydrogen, which is quite a 

 big difference. The most obvious way of explaining this would be to go 

 back at least partially to the old Lea picture and say that hydrogen atoms 

 are more widely distributed to begin with then the OH radicals. 



BURTON: Not necessarily. That view represents an over-simplifica- 

 tion. All you have to do is note that the X values are different. 



ALLEN: This may not be the only possible explanation, but it is the 

 way that first comes to mind. 



MAGEE: Let me call your attention to the fact that there is just a 50 

 per cent --or what difference do you have for the H 2 and the H2O2? 



ALLEN: I think with gamma rays the H7O2 yield is about twice that 

 H 2 yield. For rays of high ionization density, the factor may be even 

 larger. 



MAGEE: Well, there cannot be as much assymetry as having all of the 

 OH in a little sphere and the H in a sphere ten times as big. That makes 

 a tremendous difference, whereas there is only a small difference. One 

 distribution is about the same as the other one, you see, in this case, and 

 you may have a little difference in the rate constants and such things. 



ALLEN: Consider your Noo/N . You want this to come out twice as 

 big for one of these as for the other. 



BURTON: What Dr. Magee is doing is presenting a theory which dis- 

 tinguishes between the R reaction and the F reaction. There is a nuance 

 here in that the F reaction is not the same for H 2 and H 2 02» and that 

 nuance can be treated in one of two ways: to have the hydrogen atoms a 

 little further out, which is far inside the distance that we think of in the 

 Lea-Gray picture, or to have them diffuse with a different mean free path. 

 Either one of these would explain this nuance. But what he is trying to do 

 is to explain this big ratio. Is that correct? 



