96 CHEMICAL REACTIONS IN THE GAS PHASE 



Hart: 



The complexity of reactions in aqueous solution is illustrated by the work of 

 Gordon and myself at the Argonne National Laboratory. We have irradiated 

 acid solutions containing dissolved deuterium gas and find that deuterium is 

 converted first to HD and then to H2. In other words, there is a gradual re- 

 placement of the deuterium gas by hydrogen gas. On the other hand, at pH 12 

 there appears to be direct conversion of the deuterium to hydrogen without the 

 formation of HD as an intermediate. This has been interpreted as indicating a 

 reaction between the OH radical and D2 to yield HOD and D ; the free D atom 

 then reacts with an 0H"~ ion to form HOD". The latter ion then exchanges 

 with the hydrogen in H2O, forming HOH~, and this decomposes to give free 

 hydrogen atoms which combine to produce molecular hydrogen. In the basic 

 solution at pH 12 there is less than 10 per cent as much HD as is obtained in the 

 acidic solution. 



Solomon : 



We have been using a mass spectrograph in the determination of the abun- 

 dance of deuterium in biological samples, and read the H peak ratio with an 

 electron beam at 75 volts. Because of the formation of H3, it is necessary to 

 extrapolate the readings to zero pressure, as the H3 is pressure dependent. 

 However, th^ slope of the curve of pressure dependency does not appear to vary 

 in a discoverable way with the pressure, with the electron density, or with any 

 other known variable. In other words the Hs-ion formation does not seem to 

 be proportional to any known factor in the mass spectrograph. Is there an 

 explanation for this? 



Eyeing : 



No information is available, as far as I know. 



