43 



BURTON: I don't know whether this is pertinent and maybe Dr. Onsager 

 can tell us. Would cystine be a case where you could easily get dissociative 

 capture? That is, would H come off very easily? 



ONSAGER: I don't know much about it. 



BURTON: The strength of the carbon-sulfur bond is rather low, isn't it? 

 The HS would have a pretty good electron affinity. 



ONSAGER: That might well happen. Others here would know at least as 

 much about it. 



MAZIA: I know that you cannot preserve cystine in solution for very long. 

 It oxidizes readily, especially if the system is contaminated with traces of iron.. 



BURTON: My guess is that the S-C bond there is weak and that you should 

 have dissociative capture there rather readily as well as at the carboxyl link. 



BUTTS: You would criticize their experiments because they were done in 

 air? Is that right? 



POLLARD: Yes, I would. 



BURTON: If you had air there, you would be in an uncomfortable situation 

 in that oxygen itself captures electrons and that would tend to confuse the whole 

 issue. 



ONSAGER: In connection with the previous discussion, it might be of some 

 interest to radiate dry water. I mean ice. 



PLATZMAN: I believe that has been done, and it would be interesting to 

 hear about it. 



HOCHANADEL: Ghormley and Stewart at the Oak Ridge National Laboratory 

 have been studying the radiation chemistry of ice. The study thus far has been 

 chiefly that of the gamma ray induced formation and disappearance of hydrogen 

 peroxide as a function of total dose, temperature, concentration and the presence 

 of dissolved gas. Hydrogen and hydrogen peroxide are produced at all temper- 

 atures from 0°C down to -269°C. The initial yield decreases continually from 

 C down to -200°C below which it is nearly constant down to -269°C. Reactions 

 occur in ice which lead to disappearance of peroxide, and on long irradiation, 

 steady state concentrations are obtained. The initial rate of disappearance of 

 peroxide in hydrogen saturated ice containing peroxide, increased with temper- 

 ature in the range from -175 C to -50°C with a seven-fold increase in rate oc- 

 curring between 100°C and -50°C. On irradiating ice at -196°C there was evi- 

 dence for existence of unstable species such as free radicals or trapped charges 

 which could be released in the solid on warming to temperatures above -180°C. 

 This was shown both by chemical and optical measurements. 



ONSAGER: Do you find any connection there with the dielectric relaxation 

 of the ice? 



HOCHANADEL: Complete correlations with the dielectric properties of ice 

 have not been made, although a close similarity was noted in the variation with 

 temperature between the yield for peroxide disappearance in hydrogen saturated 

 ice irradiated with gamma rays and the dielectric constant of ice for a frequency 

 of 60 cycles per second. 



