Sturmian expansion method for bound state problems

A novel precision method is developed to solve a two-body bound state problem where the interaction may be an arbitrary relativistic, complex, nonlocal operator and, in particular, may contain also the Coulomb potential. The method is based on the expansion of the Green's function (free or Coulomb modified) in terms of a discrete set of Coulomb Sturm functions which have equally simple forms in $x$ or $p$ space representation. The method should be particularly useful for hadronic atom problems. Other applications are also suggested.