Dielectric screening in palladium

The static dielectric screening function is studied in fcc Pd, using the selfconsistent Hartree approach of Ehrenreich and Cohen (1959). The integral equation for the inverse susceptibility is solved in a number of approximations in the manner applied to Ni by Hayashi and Shimizu (1969). The results of a single d band model calculation and a combined s and d band calculation with and without core polarization effects are included along the principle symmetry directions (100), (110) and (111). In addition the N process and Thomas-Fermi results are given. The models are then compared to a long wave limit fitted dielectric function calculated from the elastic constants C 11 , C 12 , and C 44 taken from sound velocity measurements. The agreement of the 2-band result including core polarization with the long wave fitted dielectric function is extremely good and suggests that a single point-ion description of phonon effects may be useful in this metal.