Pseudojellium, ideal metals, and stabilized jellium

Two new electron gas models, introduced in the early 1990s, describe the energetics of metals better than the conventional electron gas, jellium. The first, the ``ideal metal,'' was derived by starting with jellium at a specified density and requiring that no forces act on the positive background when the system is cleaved. The second, ``stabilized jellium,'' was derived by starting with the pseudopotential model of metals, requiring that this model yield equilibrium at the specified average electron density and then averaging the potential seen by the electrons to obtain an equivalent electron gas. Even though these derivations are conceptually quite different, their results, the ideal metal and stabilized jellium models, are very nearly identical. We explain their great similarity by deriving both the ideal metal and stabilized jellium in a unified way from pseudojellium---a stabilized electron gas model derived in the middle 1980s that includes the average electron-ion interaction, while maintaining the uniform ground state and computational simplicity of jellium. This derivation explains the near identity of the ideal metal and stabilized jellium and allows us to understand the small differences between them.