We report density functional studies of the structure and dynamics of NaMg H3, KMg H3, and RbMg H3 in the cubic perovskite structure as well as the corresponding fluorides and the alloy (Na,Li) Mg H3. The hydrides are ionic materials with structural properties very similar to fluorides. However, even though the structures of the hydrides and fluorides are very similar, we find that the dynamics can be quite different. We ascribe these differences to breathing of the hydride ion. This is also reflected in a reduced tendency toward Li off-centering in (Na,Li) Mg H3.
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|State||Published - Dec 27 2007|