Theoretical Study of the Pressure Dependence of the Knight Shift in Alkali Metals

For Li and Na metals we investigated theoretically the pressure dependence of the atomic spin susceptibility χA, the probability density PF and the Knight shift Ks = (8π/3)χAPF by the spin polarized version of the scalar relativistic augmented plane wave method. The calculations were performed within the volume range V0 ≥ V ≥ 0.5 V0, where V0 is the volume at 1 bar. Recently it was found experimentally by Bertani et al. that a) the slopes of the curves Ks = Ks(V) have different signs for lithium and sodium metals and b) for high pressures Ks(V) goes through a minimum for Na metal. We found in the present investigation that this behavior can be understood in terms of a competition between the pressure dependence of χA and PF for these metals.