NMR lineshapes in solid tritium and deuterium-tritium

We report on the NMR free induction decays (FID) from solid tritium (T₂), deuterium-tritium (D-T), and H₂, HD and D₂ containing 2% tritium. The FID in pure components is typically a beat decay for spin concentrations >30%, an exponential for spin concentrations <10%, and a Gaussian or Gaussian-exponential for spin concentrations in between. In mixtures of DT or HD, the deuteron FID is a Gaussian-exponential while the T or H FID is typically a beat decay or Gaussian depending on temperature. The linewidth is shown to consist mostly of intermolecular and intramolecular contributions, with a small component resulting from unpaired hydrogen atoms created by the tritium radioactivity.