The pressure dependence of the electrical resistivity thermopower and phonon dispersion in liquid mercury

The dependence of the electrical resistivity, thermopower and phonon dispersion on pressure is investigated quantitatively with a view to determining whether the density of state parameter, g = N(E F)/N free(E F), introduced recently by Mott does exist and how it changes with pressure. By using the nearly-free electron approximation based on the pseudopotential calculated by Animalu and Heine, and the recent theoretical interference function, a(q) of Ashcroft and Lekner, our quantitative results indicate that the resistivity of liquid Hg calculated according to Ziman's theory (g = 1) is at least a factor 2 less than the experimental value (suggesting g 2<0.5) and that it increases rather than decreases with pressure, whence we deduce ∂ ln g 2/∂ ln a ~ -30, where a is proportional to the cube root of the atomic volume, in order to restore agreement with experiment.