Atomic structure of hydrogen storage amorphous alloys

Neutron diffraction is a powerful tool to elucidate the structure of hydrogen storage materials. H/D isotopic substitution was employed to observe the location of deuterium atoms because the coherent scattering length of deuterium is large enough to observe in comparison with those of the other atoms forming hydride materials. The combination of X-ray and neutron diffraction made clear the location of deuterium atoms of the hydrogen induced amorphous alloys experimentally. Moreover, the RMC modeling based on the diffraction data indicates that about 93% of D atoms for a-(Ti_0.676Zr _0.324)D_0.31 and about 98% of D atoms for a-TbFe ₂D_3.8 and a-TbNi₂D_2.4 occupy tetrahedral sites formed by metal atoms. Interestingly, during the HJA process, whereas the concentration fluctuation develops in the structure of A-TbFe ₂D_3.0, the homogeneity of the atomic arrangement of metal atoms is kept for a-TbNi₂D_2.4.