Sum rules and beyond

Abstract

Abstract Sum rules relate the integrated signals of the spin-orbit split core levels to ground state properties, such as the spin-orbit coupling, magnetic moments and charge distribution. These rules give the zeroth moments of the spectral distribution. It is shown how this can be generalized to higher-moment statistical analysis. Within the independent-particle model an expression is given which relates the spectral shape of the core-level spectrum to the expectation values of ground-state operators. Another way to detect the core hole multipole moment is to probe the core hole polarization by spin polarization and magnetic dichroism in resonant photoemission.