Electrons tunneling through an oxide layer into a sufficiently thin metal or semiconductor film can resonate with the discrete "particle-in-a-box" energy levels in the film. The theory of this effect is given in the case that the electrons couple with only one "standing Bloch wave". It is possible to deduce from experiment five parameters of the relevant group of electrons. These are the energy, velocity, effective mass, surface scattering phase shift v, and dq/dk (hk crystal momentum