Mossbauer, EPR, magnetic susceptibility, and DFT studies of the unusual two-coordinate iron(II) amide Fe[N(t-Bu)(2)](2) show that it retains a linear N-Fe-N framework due to the nonbonding delta nature of the (xy, x(2)-y(2)) orbitals. The resulting near-degenerate ground state gives rise to a large magnetic moment and a remarkably large internal hyperfine field. The results confirm that extraor...

Highly accurate soft-XMCD data recorded on a Nd2Fe14B single crystal, through the spin reorientation transition show that the average Fe orbital moment (a) is proportional to the macroscopic Fe anisotropy constant, and (b) diverges 15 K below the reorientation transition temperature. This divergence is indicative of a critical behavior and it is related to a tetragonal distortion. These results...

Pyruvate formate-lyase activating enzyme (PFL-AE) catalyzes the generation of a catalytically essential glycyl radical on pyruvate formate-lyase (PFL). Purified PFL-AE contains an oxygen-sensitive, labile [4Fe-4S] cluster that undergoes cluster interconversions in vitro, with only the [4Fe-4S](+) cluster state being catalytically active. Such cluster interconversions could play a role in regula...

It is shown by neutron diffraction and Mossbauer spectrometry that the formation of a long range magnetic order in zinc ferrite depends sensitivily on the content of divalent iron. The experimental data favour a non collinear model of the magnetic structure. Zinc ferrite is a normal spinel with the tetrahedral A sites occupied by Zn2+ ions and the octahedral B sites occupied by Fe3+ ions. Any m...

The inelastic scattering of x-rays, one of the the first applications of x-rays to the field of condensed matter physics, has been rejuvenated in the last decade. The availability of synchrotrons radiation from wiggler and undulator sources combined with advances in monochromatization of the incident beam and analysis of the scattered beam with meV resolution led to the measurement of phonon di...

Nanospray and collisionally-induced dissociation are used to evaluate the presence and absence of interstrand co-chelation of zinc ions in dimers of metallothionein. As was reported in a previous publication from this laboratory, co-chelation stabilizes the dimer to collisional activation, and facilitates asymmetrical zinc ion transfers during fragmentation. In the case of metallothionein, dime...

— The overall stoichiometry compensation through transition ion valency changes has been studied in CuGaS2. For this purpose, Ni and Fe were used as ionic sensors of the matrix state, as these impurities are already present in the as-grown material. The valency changes could be observed either by electron spin resonance or Mossbauer absorption. With increasing sulphur content, the valency of Fe...

In the analysis of time-reversal and Mossbauer absorption experiments, it is important to consider atomic processes which interfere with the dllect nuclear transition. Interaction of the photon with the atomic electrons causes the radiation to acquire a phase shift,-specified by the interference parameter s(L1T). We present theoretical expressions for 5 and compare our calculated values with ex...