  We followed the evolution of the normal and superconducting properties of Al
thin films after each session of various successive oxygen irradiations at
ambient temperature. Such irradiated films, similar to the granular ones,
exhibit enhanced superconductivity, Kondo behavior and negative-curvature
resistivity. Two distinct roles of oxygen are identified: as a damage-causing
projectile and as an implanted oxidizing agent. The former gives rise to the
processes involved in the conventional recovery stages. The latter, considered
within the context of the Cabrera-Mott model, gives rise to a multistep process
which involves charges transfer and creation of stabilized vacancies and
charged defects. Based on the outcome of this multistep process, we consider
(i) the negative curvature resistivity as a manifestation of a
thermally-assisted liberation of trapped electric charges, (ii) the Kondo
contribution as a spin-flip scattering from paramagnetic, color-center-type
defects, and (iii) the enhancement of T_{c} as being due to a lattice softening
facilitated by the stabilized defects and vacancies. The similarity in the
phase diagrams of granular and irradiated films as well as the aging effects
are discussed along the same line of reasoning.
