Spin polarization of the photoelectrons and photon polarization of x-ray absorption: Spectroscopy and magnetometry

We introduce here how to perform spectroscopies that are sensitive to the spin polarization of the electron states, via the direct measure of the P vector of a (photo)electron beam in a suitable experimental set-up and how to perform photoemission/photoabsorption experiments that, by exploiting the polarization of the exciting photon beam, are directly sensitive to the spin order in the initial state revealing, for example, the magnetization state of solids and surfaces or the effects of spin-orbit interaction in the surface electronic structure.