Isomeric Effects in Fragmentation by Beta Decay: Monotritiated Propanes and Toluenes

Publisher Website
Google Scholar
Abstract
The spectra of positively charged fragments from beta decay of tritium in primary and secondary monotritiated propane and in o‐, m‐, p‐, and α‐monotritiated toluene have been determined by mass spectrometric techniques. Although the number of products from decomposition of each molecule is quite large, the mass patterns from the two propanes are fairly similar while the four mass spectra from the isomeric tritiated toluenes are very nearly the same. These results suggest that the influence of the location of the radioactive atom in the molecule on the fragmentation following beta decay is often obscured by secondary processes, such as radiationless transitions, H‐atom migration, and other rearrangements of the excited molecular ion before breakup. However, there are significant differences within the two groups of mass spectra. Some of the differences in the propane patterns are consistent with the greater stability of the secondary propyl structure as compared to that of the primary isomer. Energetically plausible decomposition schemes for the tritiated propanes are proposed. The distributions of excitation energies made available to the daughter molecular ions (C3H7He3)+ in the beta transformation of H3 to He3 are estimated.