Neutron-diffraction observations on the palladium-hydrogen and palladium-deuterium systems

Neutron-diffraction investigations on powdered samples have shown that both hydrogen and deuterium atoms in β-phase Pd-H and Pd-D are located in the octahedral positions of the palladium lattice. Results obtained for samples with low gas concentration are inconclusive in determining the atomic positions in the α-phase, since at room temperature only a small amount of gas enters this phase. Although the vibrational amplitudes of hydrogen and deuterium are similar to those observed in other compounds, the total neutron-scattering cross-section for hydrogen in this system is abnormally low, indicating that the protons are more nearly free than in the other hydrogen compounds.