General theory of double nuclear gamma-magnetic resonance

A theory of emission, scattering and absorption of γ-quanta by the Moessbauer nuclei is developed for the case, when the NMR transitions are induced between nuclear sublevels both in the ground and excited states. The scattering amplitudes and cross-sections under conditions of this double resonance are calculated. The result for the emission spectrum differs from the known Gabriel's expression in extra interference terms. (author)