Multiple scattering theory: a general partitioning approach

We derive here a general, basis-independent, multiple scattering theory in a partitioned space. For this, we decompose a given set of atoms into non-intersecting subsets and construct the multiple scattering theory associated with these objects. We show that all the actual theories of electron spectroscopies are particular cases of our theory but that many other choices can be made to give a more adequate description of these spectroscopies. In that way, this theory is highly customizable to the problem under study.