DISCUSSION , 69 



with ionization transfer between molecules and also with ionization transfer 

 within the molecule. Before a process of thermal degradation of energy occurs 

 there is perhaps a situation not too different from that in a photochemical 

 process. However, the process of thermal excitation is not to be compared with 

 that in reactions induced photochemically or by ionizing radiations. 



Livingston: 



There are cases in radiation chemistry where the products are like those 

 produced in thermal reactions. Examples of this type are the decarboxylation of 

 organic acids and the splitting of hydrocarbons into two stable molecules. On 

 the other hand, no one can deny that there are photochemical and radiation 

 chemical reactions whose products are predetermined by the manner of acti- 

 vation. The interesting thing is not that there are these differences, but that 

 the reaction products of complex molecules are so often independent of the 

 manner of activation. 



Magee : 



It is somewhat unfortunate that there is so much talk of ionization of the 

 individual atoms of a molecule. Ultimately the charge always resides in the 

 valence electrons and must belong to the molecule as a whole, not a single con- 

 stituent atom, except in special cases. However, there are differences in the 

 distribution of charge in a molecule ion characteristic of the particular energy 

 state involved in the ionization. It is this average depletion of electron charge 

 in a part of the molecule to which reference is properly made by the expression 

 that a particular group or atom in the molecule is ionized. 



Concerning the breakdown of selection rules in impact processes it is, of course, 

 true that almost all selection rules are violated for very close collisions of any 

 fast particle. However, most of the effect on the matter in any irradiation is 

 due to the relatively slow secondary electrons. Here exchange effects must be 

 considered between the secondary electron and the electrons of the molecule 

 with which it collides. The ordinarily forbidden singlet-triplet transitions occur 

 with high probability. 



Solomon : 



I should like to point out that the process of "flow" of ionization is an im- 

 portant one in the operation of Geiger counters, where it is relied upon in order 

 to quench the pulse. Perhaps one could use the quenching time in a Geiger 

 counter to obtain further information on how quickly the ionization flows. 



Dale: 



Is the theory that the hydroxyl and hydrogen ions are responsible for the 

 denaturation of proteins meant to substitute for the theory of radicals? 



Livingston : 



It is probable that both means of denaturation are effective. Their relative 

 importance is not known. 



