Fermi surface distortionst

The energy independent model pseudopotential (EIMP) formalism, developed in the preceding paper, and Shaw’s optimized model potential (OMP) formalism are applied to first principles calculations of phonon spectra of the alkali metals and AI and of Fermi surface distortions for the alkali metals. Then the applicability of the EIMP formalism for calculating actual physical quantities needed to characterize metal properties is examined in relation to Shaw’s OMP formalism. It is found that, although both formalisms are able to give reasonable agreement with experimental phonon spectra, results calculated by Shaw’s OMP for the Fermi surface distortions are much worse than the EIMP results and, in particular, are too sensitive to the uncertainty in the model potential parameter A 2 due to its energy dependence to be determined definitely for the heavier alkali metals. On the other hand, when compared with existing APW calculations for Fermi surface distortions, in which the relativistic effect due to the deep-core electrons is omitted, i t is found that the EIMP results are about the same as existing APW results for the light alkali metals and better for heavier ones. It then appears that the relativistic effects due to the deep-core electrons on the Fermi surface distortions, which is taken into account implicitly through the model potential parameters in the EIMP calculation, are rather significant for heavier metals.