Electron correlation and magnetism in molecules and solids.

Abstract

In order to understand the magnetic properties of solids and molecules, an accurate description of the underlying microscopic many-electron systems is required. This can be achieved through several theoretical and computational methods, which account for the electron-electron interactions and for quantum effects within different levels of approximation. In this thesis, we apply some of these methods [density functional theory (DFT), Hartree-Fock (HF), random phase apj)roximation (RPA), continuum and lattice quantum Monte Carlo (QMC)] to the study of various problems of current interest within the field of spintronics.