Sturm expansions of the Green's functions for very simple systems

Sturmian expansions of Green's functions for a number of physical models, such as the generalized Kepler problem, nonrelativistic as well as relativistic hydrogem atom, harmonic oscillator and Morse oscillator, are obtained. General scheme for the construction of complete sets of sturmian functions is considered. It includes as a particular case the problem previously investigated, where the eigenvalue is the strength of the potential.