Observation of Interference Effects in the Mössbauer Absorption Spectra of E 2 and E 2 M 1 Transitions

In a transmission geometry, dispersion terms were observed in the shapes of the M\"ossbauer resonance lines of pure $E2$ and mixed $\frac{E2}{M1}$ transitions. For the pure $E2$ transitions studied, the relative magnitude of these terms, which are attributable to interference effects, is typically 1.5% of the depth of the absorption line. We discuss possible consequences of the resulting asymmetric line shape for isomer-shift measurements.