An investigation was made of the permeation of normal H, and of H which was enriched with para-H, through a Pd-23%Ag membrane. At temperatures ranging from 350 to 400K, the activation energy for permeation was equal to 4.9kcal/g-atom for normal H, and equal to 3.54kcal/g-atom for H which was enriched with para-H. The differing activation energies were attributed to the differing dissociation energies of normal H and of H which was enriched with para-H.

L.Fitoussi: Comptes Rendus, 1968, 267[26], 1742-5