Electron-Gas Spin Susceptibility

The wave-vector-dependent spin susceptibility of an electron gas is calculated taking dynamically screened electron interactions into account. A quasiparticle approach is developed to deal with the self-energy and screening effects of the electron correlations, and the energy and mass of a quasiparticle at the Fermi surface are calculated for a wide density range. The susceptibility is found using a linearized self-consistent-field treatment of the quasiparticles and numerical solution of the resulting integral equation. It does not show singular or anomalous behavior at large wave vector as in the Hartree-Fock approximation. The density dependence of the zero-wave-vector susceptibility is found to be in better agreement with experiment than that of previous calculations. Statically screened interactions are also used in a series of calculations, and it is shown that a long- but finite-range interaction can lead to anomalies in the susceptibility at large wave vectors.