E.R. Bauminger

Goldanskii effect in quadrupole Mössbauer spectra of the 89 keV gamma ray of 156Gd

Abstract Unusual relative line intensities in the recoilless absorption spectra of the 89 keV gamma ray of 156Gd in Gd2Ti2O7 have been observed at various temperatures. The results prove that the unusual intensities are mainly due to lattice vibrational anisotropy.

Magnetically induced electric field gradients and hyperfine fields in UFe2, NpFe2 and PuFe2☆

Mossbauer studies yield the easy magnetization directions and the hyperfine interactions in UFe2, NpFe2 and PuFe2. Magnetically induced electric field gradients observed previously only in a few cubic insulators, are observed for the first time in a metallic noncubic environment.

Large Goldanskii effect in quadrupole Mossbauer spectra of the 103.2 keV gamma ray of 153Eu

Abstract A large Goldanskii effect was observed in the recoilless absorption spectra of the 103.2 keV gamma ray of 153 Eu in Eu 2 Ti 2 O 7 . Values for the quadrupole interaction parameters, the crystal field parameter V 0 2 keV gamma ray of 153 Eu and the shielding parameter σ 2 were deduced.

Charge states of Np recoil atoms following α decay

Abstract Utilizing the Mossbauer effect, the charge states of the Np ions in various Am sources were determined. The charge states were found to be +3 in all sources containing the Am ions in frozen solutions and +4 and +5 in all oxide sources. In most other Am salts the Np attained the valence of the host lattice.

Origins of supertransferred hyperfine fields acting on 119Sn in iron garnet systems

Abstract The supertransferred hyperfine field acting on 119Sn in YIG (209.5 ± 0.5 kOe) originates mainly from the tetrahedral iron first nearest neighbours. -2 ± 2 kOe and 13 ± 2 kOe are the respective contributions of farther octahedral and tetrahedral iron shells. The ratio of g exc / g o obtained from the present measurements is -0.2150 ± 0.0005.

Magnetic moment of the 91 keV excited state of 149Pm

Abstract Recoilless absorption measurements of the 91 keV γ -rays of 147 Pm, with a 147 NdA1 2 source and a radioactive 147 Pm 2 O 3 absorber, yielded a value of 1.925 ± 0.004 for the ratio of the g-factors of the 91 keV level and the ground state of 147 Pm.

Electric field gradients and crystalline fields in europium iron garnet

Abstract The electric field grandients acting on europium nuclei in the two inequivalent sites of EuIG were measured. The various contributions to the electric field gradients are discussed.

Ferredoxin from Halobacterium of the Dead Sea--Mössbauer and EPR spectra and comparison with Mössbauer spectrum of whole cells.

Recoil-free measurements were carried out on a 2 Fe-ferredoxin, which was isolated and purified from an extreme halophile, Halobacterium of the Dead Sea. The spectrum of this ferredoxin in the oxidized state at 82 K is a superposition of two quadrupole doublets, representing two non-equivalent Fe3+ sites of equal intensity. The spectrum of the reduced ferredoxin is consistent with the presence of two pure classes of iron atoms, ferric (lower isomer shift) and ferrous (higher isomer shift). Interpretations of the recoil-free spectra are discussed. Mössbauer measurements were also carried out on frozen whole bacterial cells and the resulting spectrum was found to be quite different from that observed in the isolated ferredoxin. Tentative conclusions are reached concerning the localization of this ferredoxin in the cytosol of the Halobacteria.The EPR spectrum of the reduced ferredoxin obtained at 24 K exhibits rhombic symmetry with the following g values: 1.894, 1.984 and 2.07. These values are similar to those obtained with 2 Fe-ferredoxins of the plant type, except that the gy and gz values are somewhat higher. Both from the EPR and Mössbauer data, it is deduced that the spin relaxation times in reduced halophilic ferredoxins are faster than in the reduced plant ferredoxins.

Experimental evidence for a canted spin structure in substituted rare-earth iron garnets

Abstract Mo¨ssbauer effect studied prove that the spins of the iron in the tetrahedral sites of scandium substituted rare-earth iron garnets are canted relative to the [111] direction.