Paramagnetic Hyperfine Structure and Relaxation Effects in Mössbauer Spectra:Fe57in FerrichromeA

Iron Substitution in Soil and Synthetic Anatase

“…Its 293 K spectrum exhibited a very wide resonance (Figure 6b) without any structure except for two differently broadened peaks at -0.1 and +0.4 mm.s -1 (Figure 6a). Such S7Fe-M6ssbauer resonance is typical for slow electronic relaxation (Wickman et al 1966), which is confirmed by the appearance of hyperfine splitting at 4.2 K demonstrating the effect of temperature on the relaxation time. For ~TFe, relaxation of the electronic spin is usually faster than the lifetime of the excited M6ssbauer state (141 ns).…”

“…At low temperatures this phenomenon can cause hyperfine splittings that often resemble those obtained in magnetic hyperfine fields up to 55 T. At higher temperatures the relaxation rate increases, but in some cases paramagnetic hyperfine splittings or at least substantial line broadening caused by intermediate relaxation rates persist even at room temperature. When fitted with relaxation lines as given by Wickman et al (1966), one set of hyperfine patterns corresponding to high spin Fe In yields good correspondence to the 4.2 K as well as to the RT spectrum (Figure 6a and b), but does not reproduce the doublet structure found in the center (Figure 6a) showing that the model applied cannot describe these relaxation mechanisms in detail. The set ofhyperfine parameters of the well resolved sextet of Figure 6c is IS = 0.28 (1) 32 (18) 68 (18) ram.…”

Pressure-induced suppression of charge order and nanosecond valence dynamics in Fe2OBO3

“…The resonance structure in the wings of the spectrum as well as the central pronounced asymmetric (doublet) features are signatures of paramagnetic hyperfine structure (PHS), involving spin-spin or spin-lattice relaxation. [23][24][25][26] The complexity and features of this spectrum suggests spin relaxation times ranging from 0.1 to 10 ns. 23 This range is a consequence of a distribution of interaction pathways in the complex lattice structure with multiple Fe sites.…”

Magnetism of ferriprotoporphyrin IX monomers and dimers

“…In general, it requires application of the spin Hamiltonian formalism [15]. For S=5/2 and nuclear spins, I e =3/2 and I g =1/2, for the excited and ground states, respectively, it leads to the consideration (2S+1) Â (2I e +1) Â (2S+1) Â (2I g +1)=288 transitions in the Mössbauer spectrum.…”