ON THE RELATIONSHIP BETWEEN COEFFICIENTS OF THERMAL-EXPANSION AND HEAT-CAPACITIES OF SIMPLE CUBIC METALS

Recently, an inverse-power-type interatomic potential energy function was employed to calculate the ratio between the thermal expansion coefficient and heat capacity of simple metals. However, as different interatomic potentials usually have a varying degree of success in explaining the properties of solids, the authors decided to attend to the same problem by applying another widely used potential energy function, the Morse potential, and compare the results. The results indicate that some improvements have been achieved with the Morse potential over the inverse-power-type potential energy function. This, however, is not surprising in light of the following facts: Unlike the Morse potential, the lattice sums are independent of the homogeneous deformations of the lattice in the case of inverse-power-type potential energy function. The energy of the lattice is not, therefore, coupled with the lattice geometry in the case of the latter potential.