68 



is a metastable molecule which has an energy of about 2 ev higher than the 

 ground state. It is an isomer of H2O, a linear, triplet isomer. 



PLATZMAN: Why isn't it formed in a Franck-Hertz experiment? 



MAGEE: Possibly it is. 



PLATZMAN: The Franck-Condon principle would not allow such a trans- 

 ition directly, but it might be possible to go up about 4 or 5 volts and then go 

 down to such a state by rearrangement. 



BURTON: That does not mean it lasts forever. Such an excited mole- 

 cule may enter into chemical reaction and there are also other ways that it 

 can disappear in water. 



PLATZMAN: Should we say we all look upon this with skepticism and 

 great interest? 



MAGEE: I see no reason to be skeptical. I think it is rather certain 

 that there is a stable triplet linear state of H 2 0. The energy of the state 

 is, of course, not well determined. 



PLATZMAN: Do you think that if it does exist it could be important in 

 kinetics? 



MAGEE: I think it might be. Perhaps even in radiation chemistry. 

 Such states can be formed by recombination of H and HO radicals and you 

 may get them in great abundance. 



PLATZMAN: Then pairs of these metastable molecules might give chem- 

 ical reaction? 



MAGEE: Possibly. I don't know what they do. 



KAMEN: The impression that comes to me as an intermediary here is 

 that it seems now to be rather stupid to look for an experiment to find out 

 how much energy it takes to make an ion pair in water. 



ALLEN: The question that has experimental meaning, at least in some 

 connections, is how much energy it takes to make a radical pair. 



PLATZMAN: At Oberlin I pointed out that the very concept of ionization 

 is very vague in water (17). 



KAMEN: Yes, it is beginning to percolate. 



BURTON: There is a series of papers by Hart (18), for example, who 

 has been using the term "radical pair yield" for a long time. 



BOAG: The question I should like to have answered is whether the 

 ejected electron in water returns to its parent ion or whether it becomes at- 

 tached to another molecule some distance away. If Dr. Platzman is right, 

 then there is_ meaning in speaking of ion pairs in water. 



BURTON: If there is meaning in speaking in terms of ion pairs in wa- 

 ter, then this may be one of the few liquid cases in which this meaning sur- 

 vives. It becomes less probable in ammonia, and very improbable in a liq- 



