l am not a physics expert (computational science) however I believe much of the preceding discussion seems to ignore that the hydrogen embedded in a nickel matrix could have a highly modified orbital structure. Has anyone explored the orbital differences or looked for tunneling possibilities because of the combined pressure and interaction with the coulomb shell formed by the enclosing nickel.
I found several papers illustrating dramatic effects for atoms confined in buckyballs including hydrogen::
"A unique situation for an endohedral metallofullerene", Connerade et al,J. Phys. B: At. Mol. Opt. Phys. 32 (1999) L395–L403,IOP Publishing
"Endohedrally confined helium: Study of mirror collapses", Mitnik et al, PHYSICAL REVIEW A 78, 062501 2008, DOI: 10.1103/PhysRevA.78.062501
"The finite-volume Dirac–Hartree–Fock method for confined relativistic many-electron systems", Gruchowski and Szmytkowski, J. Phys. A: Math. Gen. 37 (2004) 7783–7798 , doi:10.1088/0305-4470/37/31/010