Temperature Dependent Frequency Shifts in the Resonance Absorption and Resonance Fluorescence Scattering of Mössbauer γ‐Quanta

The relativistic Doppler effect in the resonance absorption and resonance fluorescence scattering of Mössbauer γ‐quanta of a 57 Co source is investigated in the temperature range 295 K ≦ T ≦ ≦ 585 K. The temperature shift of the resonance is d(ln ω)/d T = − (2.38 ± 0.07) × 10 −15 K −1 in absorption and − (2.67 ± 0.10) × 10 −15 K −1 in backscattering. The data are compared with Bragg scattered Mössbauer γ‐quanta from the (200) reflection of NaCl in the same temperature range. A limit d(ln ω)/d T ≦ 7.5 × 10 −17 K −1 is obtained.