Figure 4. Potential curves and wave functions along the ‹100›, ‹110› and ‹111› directions in an fcc metal lattice.

D atom is located at the (a) O site and (b) T site. Wave functions are shown for the ground state (broken lines), first-excited states (solid lines) of the vibrational states of D atom at the O site, and ground state (broken line) at the T site. The distance from the original point of the O-site centre is scaled by the fcc lattice constant a (that is, 3.720 Å), which was obtained from the neutron diffraction profile observed at 988 K and 6.3 GPa.