APPLICATION OF PSEUDOPOTENTIALS TO SODIUM-PALLADIUM ALLOYS

Pseudopotential theory as developed during the 1960s has allowed the calculation of physical properties of many simple metals. Later work has extended the use of the method to alloys of such metals. A more recent development in the field has provided model potentials for the transition metals. However these have been difficult to verify experimentally. This work addresses the application of the method to an alloy of sodium and palladium. The use of highly sensitive servo techniques allows precise measurements of the speed of sound in dilute Na-Pd alloys. Comparisons of the speed of sound in the alloy and pure metal yield the solubility which in turn is used to derive the excess entropy and enthalpy of mixing. The effect of speed of sound due to small amounts of palladium up to the saturation level is given. This data is compared to predictions based on a first principles calculation. Calculated properties include the hard sphere diameter, the change in the speed of sound, the enthalpy of mixing and the entropy of mixing.