Hydrogen movement in cubic Mg2NiH4 -: art. no. 064306

The motion of hydrogen atoms in Mg2NiH4 is studied based on ab initio total-energy calculations using the full potential linearized augmented plane-wave method. We calculate the jump frequency for two kind of rotations of the NiH4 complex through classical rate theory. The obtained jump frequencies are 4 x 10(13) e(-1.29eV/kT) s(-1) and 3 x 10(13) e(-0.67eV/kT) s(-1) for in-plane and out-of-plane rotations, respectively. These values agree well with experimental data as concluded from solving the equation for the linewidth within the Bloembergen-Purcell-Pound theory of nuclear magnetic resonance.