Gruneisen parameters, electron-phonon enhancement and superconductivity for Pd-H alloys

Measurements of the low-temperature (1.5-30K) and room temperature thermal expansion have been made for palladium-hydrogen alloys with H/Pd<or approximately=0.7. The low-temperature data have been resolved into the individual electronic and lattice components and values for the corresponding Gruneisen parameters in the zero-temperature limit have been calculated. The influence of the optic modes on the volume dependence of the electron-phonon interaction parameter and its relationship to the contribution to gamma e from the electron-phonon enhancement and the magnitude of the pressure dependence of the superconducting transition temperature of PdH is discussed.