Medium (IMAGE) Kazan Federal University Caption Energy scheme of the radioactive source of 14.4 keV photons and the vibrating absorber used in the experiment. The 57Co nuclei (left side) in the state |d? decay to 57Fe nuclei in the excited state |c? (with a half-life of T1/2?272 day), followed by cascade decay: |c??|b? (with decay time T?12??ns) and |b??|a? (with decay time TS?141??ns) with emission of 122 and 14.4 keV photons (shown by blue and green lines), respectively. Depolarized recoilless 14.4 keV photons ( λ?0.86??Å) resonantly interact with transition |1??|2? of 57Fe nuclei when propagating through the single-line 57Fe absorber (right side). They are resonantly absorbed in motionless absorber (black lines). Harmonic vibration of the absorber as a whole (pistonlike vibration) with circular frequency Ω, amplitude R, and initial phase ϑ along the photon propagation direction (marked in red) leads to periodic temporary variation in |1??|2? transition frequency ω21(t) (dashed red curves) due to the Doppler effect. It modifies the interaction of the photon with absorber and can result in AIT (see Fig. 2 and text). The axis z labels the laboratory reference frame, red axis z' labels the reference frame of the vibrating absorber, and Δz=z?z'. Credit Kazan Federal University Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.