10 



magnitude for some forbidden transitions; for example to triplet states, which 

 might lead to chemical reaction. 



KAMEN: What are the energies of the electrons in an electric discharge? 



BURTON: I felt that question coming. Although one always thinks of an 

 electrical discharge process as being very violent, it turns out that the ener - 

 gies of the electrons are for the most part of the order of 2 ev or less. This 

 means that the temperature turns out to be rather small. Of course, in the 

 particular case discussed, there was a very non-Maxwellian distribution of en- 

 ergy, apparently because of the turbulent conditions of discharge. In such 

 case there is perhaps a long high-voltage tail, but the low-voltage electrons in 

 non-Maxwellian distribution predominate. There are enough such electrons to 

 excite very low- lying states to an important extent. In the work I mentioned, 

 the first step corresponding to Dr. Kasha's suggestion was conversion of meth- 

 ane to methyl. Methyl turns out, in our opinion, to have a carbon-hydrogen 

 bond dissociation energy a little lower than that in methane. The significant 

 state, in this case quadruplet, is consequently also a little lower. Thus, the 

 second activation leads directly to decomposition of the methyl itself. In other 

 words, successive excitations are necessary for the effect observed. Without 

 sufficient energy, only methane is observed. The methyl won't be excited, and 

 there will be no product of its decomposition. 



ONSAGER: It combines with other methane? 



BURTON: No, not under these conditions. The cross section for the low- 

 voltage excitation process appears so high that methyl is substantially removed 

 very quickly. The importance of such an effect can be seen from two calcula- 

 tions from formulas for non-Maxwellian distributions: the Townsend approxi- 

 mation and the Morse approximation. The steady state concentration of CH3 at 

 an assumed electron temperature of 0. 5 ev and an assumed C-H bond strength 

 difference of 0.3 ev is less than 10 -19 that of CH4. (26) 



ONSAGER: With what does methyl combine? 



BURTON: Ordinarily, if you let it wait around long enough, it will react 

 with hydrogen and give you methane under these conditions, but in an electric 

 discharge it yields CH2. a rather stable radical. The triplet state in CH 2 

 seems to be higher than that in methane. 



ONSAGER: But suppose the intensity is low. Then the CH back reacts 

 back with hydrogen? 



BURTON: Well, I cannot talk from my own work because I have not done 

 this. Other people have done experiments at low pressure and have obtained 

 considerable amounts of ethane -- but I suspect more back reaction such as 

 you suggest than anything else. 



LINSCHITZ: What would be the dose rate in these experiments you speak 

 of, relative to the dose rate in the electron bombardment of the enzyme films? 



BURTON: There is no way of comparing them. I just don't know what their 

 dose rates are. Undoubtedly, the dose rate may be very much higher in their 

 experiments. 



LINSCHITZ: Also the rate of deactivation of the molecule in the gas would 

 be much less than that of an excited molecule in a solid, so that for both these 



