¹H NMR Study of Echo Decays in High J=l Concentration Solid H₂ and D₂

We have studied the echo decays in high J= 1 concentration solid hydrogen (H2) and deuterium (D2) using 'H NMR. In solid H2, where the ortho-para conversion is rapid, quick measurements were made possible by computer batch files containing pulse programs. In solid D2, 1% normal H2 (nH2) impurities were used as a probe for the D2 lattice. Comparison of the echo decay constants in the two systems shows that the decay of echos comes from the intramolecular interactions.