Selective excitation double Mössbauer resonance method

Integral and analytical formulae are derived for the shape of the time independent selective excitation double resonance line and used in the numerical analysis of its thickness and resonant isotope abundance dependence. The conclusions derived from this analysis are supported by a selective excitation double resonance experiment performed for an enriched metallic iron foil. The selective excitation double resonance spectra measured for a natural magnetite show no evidence of an electron hopping relaxation process. [Russian Text Ignored].