The photoelectric yield spectrum, proportional to the absorptance, of thin metal films is calculated. The film is described by either a dielectric function having a discrete single-particle excitation spectrum or, for comparison, a continuous spectrum (Lindhard). A numerical example of a 15 Å thick potassium film on a substrate is given to illustrate the changes in absorptance when the dielectric response is described differently. In the frequency derivative of the absorptance spectrum structure due to bulk plasmon resonances, well in accordance with experimental data, as well as single-particle excitations, not yet looked for experimentally, are found. We predict structure due to single particle excitations in electron energy-loss spectra.