In experiments [1,2] on irradiation of metal surfaces by ions of keV energy, the emission of X-ray laser beams from the metal was observed not only during the irradiation but also 20 hours after it was switched off (from the "dead" sample). In contrast to an usual laser, the emitted collimated X-ray beams were of continuous frequency. In this paper the mechanism of that phenomenon is proposed. Subatomic electron states are formed inside the metal. These states are associated with anomalous well within the subatomically small (10 −11 cm) region. Anomalous well is formed by the local reduction (of M eV scale) in that region of the vacuum energy of the mass-generating field. States in anomalous well are long-living which results in population inversion and the subsequent laser generation observed. The energy of emitted X-ray beams are due to the conversion of the vacuum energy of the mass-generating field (X-ray laser beams from vacuum).