The Relative Abundance of HT and HTO in the Atmosphere

Abstract

A kinetic discussion of the HT and HTO formation in the atmosphere indicates that the ratio of about 1 HT to 1000 HTO in nature and the very high T concentration of 4.10^‐15 in atmospheric hydrogen compared with about 3.10^‐18 in normal rain water can only be understood by means of a photochemical reaction. Since the tritium atoms are quickly removed by oxygen molecules in three‐body collisions and form the TO₂ radical which in turn forms HTO, the TO₂ must be photochemically dissociated. The T atoms thus set free collide repeatedly with hydrogen atoms and undergo to a certain extent the exchange reaction H₂+T=HT+H. On the other hand, the T atoms or TO₂ radicals may react with ozone to form a OT radical which combines with the hydrogen of the atmosphere into HTO. In low altitudes the reaction of TO₂ with air polluting bodies form HTO predominately. The ratio of these reactions is responsible for the ratio of HT and HTO in nature with the HTO brought down into the surface waters by rainfall.