Basis-independent multiple-scattering theory for electron spectroscopies: General formalism

I present here a general formalism that allows the construction of the cros s section of any electron spectroscopy in a straightforward and transparent way. This approach does not make any assumption concerning the choice of t he basis functions used to expand the wave function of the electron. In thi s sense, it generalizes existing theories. It allows us to keep the physics well in view and offers, due to the relationship between operators and par ts of a pictorial representation of the experiments, a type of a graphical interface to the problem at hand. Moreover, it does not assume any particul ar shape for the potential.