On the model pseudopotential approach to calculate the lattice mechanical properties of thorium

The applicability of model pseudopotential approach to investigate lattice mechanical properties of thorium, a typical f-shell metal, has been examine d in light of some recent experimental and theoretical studies. It is found that presently available model potentials do not account for s-d-f hybridi zation adequately. The equation of state is greatly affected by s-d-f hybri dization. It is also observed that a model potential giving reasonably good phonon dispersion curves may not reproduce equally good density of phonon states and hence the related lattice mechanical properties. However, it is possible to have a model potential that may give fairly good estimate of la ttice dynamical properties.