36 



mean that a "hole" is present. 



LINSCHITZ: If you hydrate the OH which is going to be formed on the side 

 of this structure, isn't that the problem? 



PLATZMAN: No, because there is no vacuum inside the orbit. There may 

 even be one water molecule preferentially close to the center. 



LINSCHITZ: So you are really hydrating over quite a volume? 



PLATZMAN: Of course. The radius is quite large. 



ONSAGER: Shall I talk about a competing process, because I think it can 

 settle the recombination question? Ionic recombination processes cannot go 

 any faster than the ions can find each other, and there is an old theory, fifty 

 years old, for recombination of this positive and negative ion. It depends just 

 on mobility and the dielectric constant. 



PLATZMAN: What is the relaxation time? 



ONSAGER: You get about the right result if you use the formula for the 

 Maxwell relaxation time, and feed into it the sum of the concentrations of the 

 recombining ions, and the arithmetic mean of their mobilities. 



PLATZMAN: What order of magnitude ? 



ONSAGER: At the conductivity of water, it would be about 10~ 5 second. 



BURTON: Does your statement apply to solvated electrons plus solvated 

 hydrogen ions? 



ONSAGER: It does. 



PLATZMAN: It doesn't matter. 



BURTON: I would like you to consider the unsolvated electron plus the 

 solvated hydrogen ion. 



ONSAGER: This is the minimum time it takes for two ions solvated or un- 

 solvated. It does not matter. They have certain drift speeds, and it turns 

 out that the electrostatic attraction is more important than just a purely ran- 

 dom motion. 



PLATZMAN: You still consider that to be correct in order of magnitude? 



ONSAGER: It is still a minimum. There might be other steps and the 

 process might be slower. But, of course, the ions cannot react before they 

 get together. 



BOAG: You are assuming a random distribution of the ions whereas they 

 are actually produced in high local concentrations. 



ONSAGER: The question is whether the electrons will be combined with 

 the hydrogen ions that happen to be present in the water to begin with. 



ALLEN: What are the concentrations here? I don't quite understand your 

 relaxation time. 



