Observation of Molecular Motion in SolidH2Below 4.2°K

Abstract
NMR measurements in solid H2 at low ortho concentrations between 0.4 and 4.2°K show that the equilibrium distribution of ortho molecules in the lattice is temperature dependent and is approached approximately exponentially in time at a given temperature. It is suggested that the rearrangement process occurs by means of ortho-para interchange.