Prediction of Fermi-Surface Pressure Dependence in Rb and Cs

The linear muffin-tin orbitals method of band-structure calculation, combined with a Gaussian integration technique using special directions in the Brillouin zone, has been used to calculate Fermi radii and extremal cross-sectional areas of the Fermi surface in rubidium and cesium. Band shifts were used to achieve optimum agreement with experimental results. Volume derivatives were then obtained by varying the lattice parameter with the band shifts held constant. The significance of this procedure has been discussed in the light of recent theoretical work. The results obtained for the Fermi-surface pressure dependence agree with the limited experimental data available.