A structural expansion of the cohesive energy of simple metals in an effective Hamiltonian approximation

Abstract

In the modern theory of simple metals a large number of physical properties, such as the cohesive energy, lattice constants, lattice structure, elastic constants and vibration spectra are calculated from a self-consistent pseudopotential expansion of the total energy of the ions and conduction electrons. This expansion, which is actually a structural expansion of the cohesive energy valid for an arbitrary arrangement of the ions, has only been known to second order. In the present paper the third-order term in this expansion is derived.