Analysis of charge and spin densities

Abstract

This chapter describes the interaction of X-rays, unpolarized and polarized neutrons with the charge and spin densities of a periodic system. The methods developed for analysis of the electron densities from the diffraction intensities are described in detail and the concepts used in the interpretation of the results are defined. Keywords: n-particle wavefunction; approximations; atom-centred expansion; charge densities; crystal-field approximation; cusp constraint; dipolar approximation; elastic scattering; electron density; electroneutrality constraint; electrostatic moments; electrostatic potential; external vibrations; extinction; Hellmann–Feynman constraint; magnetic scattering; magnetic structure factors; moments of a charge distribution; multipole expansions; neutron scattering; physical constraints; polarized neutron scattering; pseudo-atom moments; radial constraint; scattering; spin density; structure factors; thermal smearing; X-ray scattering