44 



ONSAGER: Did you compare your times with the time of dielectric relaxa- 

 tion of ice? 



HOCHANADEL: No such correlation has been made. 



PLATZMAN: I might venture to suggest that it might not enter at all just 

 because the relaxation time is so great that relaxation never occurs. 



ONSAGER: It is not so very great. 



PLATZMAN: It depends on the temperature, but once you get down -- 



ONSAGER: At the freezing point it is a few micro-seconds. 



PLATZMAN: It is about 10" 5 second at the freezing point. At -170°C it is 

 many years. 



I would suggest that if you never have relaxation at all, the electron moves 

 rather freely. 



ONSAGER: I don't know about that because you might have something else. 



ALLEN: Can you tell us how long it will take this electron to be released at 

 -170? When you raise the temperature up to there, does it come out in a mat- 

 ter of minutes or does it take hours? 



HOCHANADEL: It is a matter of minutes. 



Ghormley and Stewart showed by chemical and optical measurements that 

 unstable species such as free radicals or trapped charges are produced in ice 

 at low temperatures by gamma rays, and that these species can be released in 

 the solid at higher temperatures. Chemical measurements of hydrogen perox- 

 ide, hydrogen and oxygen were made after melting the irradiated ice; however, 

 by a method of thermal cycling with intermittent irradiations, the temperature 

 range in which reactions occurred in ice after irradiation (presumably due to 

 release of these trapped free radicals or charges) was determined. For ex- 

 ample, when a sample of ice containing dissolved hydrogen peroxide and hydro- 

 gen was subjected to two or more ten minute irradiations at -196°C and allowed 

 to warm to -180°C or above between irradiations, the observed final concentra- 

 tion of hydrogen peroxide was less than that for an equivalent continuous irradia- 

 tion at -196°C. The presence of unstable species in ice irradiated at -196°C 

 was also indicated by a broad absorption band with a peak at 2800 j^ which dis- 

 appeared on heating over a similar temperature range. 



KASHA: I might make a comment about what Dr. Linschitz has already 

 mentioned; that there is a small field of photo-chemistry in which people have 

 irradiated organic molecules in rigid glasses, using both electrons and light. 

 The "photo-oxidized" rigid solutions have been found to be paramagnetic. The 

 solvated electrons are stabilized in the rigid glass solution and they remain that 

 way until the system has been melted, after which they become unsolvated in a 

 matter of minutes or fractions of a second perhaps. That can be judged very 

 quickly by observations of the color phenomena which accompanies the desolva- 

 tion of the electrons. You see, this work goes back to the work which Lewis 

 and Lipkin (15) did. 



BURTON: With electrons ? 



