Interference of Electronic and Nuclear Resonance Absorption for MössbauerE1Gamma Rays

The large dispersion term in the absorption spectrum of the 6.25-keV ${\mathrm{Ta}}^{181}$ $\gamma$ ray which was found by Sauer, Matthias, and Mössbauer is interpreted as arising from the interference between nuclear absorption followed by internal conversion and photoelectric absorption. The interference is large because the nuclear transition is $E1\mathrm{}$.