Electron densities and related properties from the ab-initio simulation of crystalline solids

This chapter deals with the charge, spin and momentum densities of electrons in crystalline solids as obtained from ab-initio simulations. It describes state-of-the-art approaches using plane waves or local basis functions, and comments on their main advantages and drawbacks. The influence of computational parameters on densities is demonstrated by way of examples. Ongoing developments are briefly discussed: thermal effects, response to external perturbations, post-Hartree Fock treatment of electron correlation.