Forward scattering of Mössbauer radiation by thick absorbers under NMR conditions in an exited nuclear state

This work deals with the resonant scattering of Mössbauer radiation in forward direction by a thick absorber with magnetic order. We propose an excitation of the absorber by a resonant radiofrequency field (provided NMR condition in the exited nuclear state is fulfilled). We made concrete calculations for the Mössbauer isotope $^{57}\mathrm{Fe}$ and found that the resonant radiofrequency field causes the formation of satellites in the forward scattering spectra, analogously to the case of satellites exited by an ultrasound or a nonresonant radiofrequency field. We also detected the phenomenon of radiofrequency-induced partial transparency of the medium, i.e., the increase in the intensity of the Mössbauer radiation transmitted through the absorber, accompanied by the increase in the radiofrequency field amplitude.