THE ROLE OF ELECTRON-ELECTRON INTERACTIONS IN LIQUIDS

Electron-electron interactions appear to play qualitatively vital role s in the behavior of expanded liquid metals; these systems display phe nomena that simply do not occur in a single-electron picture. Motivate d by a desire to understand such liquids, and to model electron intera ction effects in liquids more generally, we show in this paper how one can formulate and solve a Hartree-Fock theory within a liquid by usin g liquid theory methods. The work generalizes the previous efforts of Logan and co-workers by removing the restrictions to model band shapes and Hubbard Hamiltonians. The Pariser-Parr-Pople Hamiltonian used her e has the added feature of an interatomic Coulombic interaction and th erefore allows us to assess the role of interaction-induced fluctuatio ns in the local field at each atom. The model also requires a calculat ion of a quantity with the significance of a bond order, a concept of some possible utility in a wide variety of electronic-structure-in-liq uids problems.