Collisions for the quantum Coulomb hamiltonian

We study the propagation of phase space singularities for the time dependent Schroedinger equation with potential having Coulomb-type singularities in space dimension equal to three. We prove that the singularities (frequency set) of the solution are reflected by a Coulomb center exactly as in the classical problem, i.e. the frequency set follows the regularized trajectories of Classical Mechanics after a collision. (orig.)