Ab initio calculation of lattice dynamics in FePd intermetallics.

The lattice dynamics of FePd and FePd(3) intermetallics have been investigated using an ab initio electronic structure method. The phonon dispersions and the contribution of each of the components to each branch of dispersion for three symmetry directions, along with the phonon densities of states, are calculated and compared with experiments. The force constants between various pairs of atoms in these intermetallics are obtained from first-principles calculations and the results are discussed based upon analysis of these data. A possible route to obtain force constants for disordered alloys from the intermetallics results is also discussed.