<i>Ab Initio</i>Calculation of the Spin Susceptibility for the Alkali Metals Using the Density-Functional Formalism

The new variational-principle, density-functional theory of the spin susceptibility $\ensuremath{\chi}$ is used to make a priori calculations of $\ensuremath{\chi}$ for the alkalis. Crystalline effects are calculated by the spherical-cell method and the local spin-density approximation is used for the exchange-correlation functionals. The excellent agreement between the results and recent experiments establishes the validity of this new theory and the correctness of the theoretical values for the exchange-correlation enhancement of $\ensuremath{\chi}$ for a homogeneous electron gas for ${\mathcal{r}}_{s}\ensuremath{\lesssim}5$.