THE FERMI-SURFACE AND PSEUDOPOTENTIALS OF ALUMINUM

The accurately determined energy levels at the W point of the FCC Bril louin zone obtained from low-temperature galvanometric measurements of the Fermi surface of aluminium are used to determine an empirical loc al pseudopotential and to test the precision of the standard scheme fo r calculations of band structure. While satisfactory for cohesive and structural properties, the standard scheme appears to reproduce the th ird-zone Fermi surface dimensions and topology rather poorly. Since th ere still remains some flexibility in the definition of ab initio pseu dopotentials, it is suggested that agreement with the major cohesive a nd structural properties can be maintained, but that with relatively m inor adjustment Fermi surface properties can also be reproduced. This notion is illustrated for the empirical local pseudopotential which is applied to the evaluation of the interatomic pair potential (which is found to be in good agreement with other calculated pair potentials) and also to a redetermination of the conductivity of molten aluminium which reveals rather clearly the limitations of the first-order Born a pproximation.