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Hyperfine Interactions In The Intramolecular Antiferromagnet (Fe Salen C1)2, R. Lechan, C. Nicolini, C. R. Abeledo, Richard B. Frankel
Hyperfine Interactions In The Intramolecular Antiferromagnet (Fe Salen C1)2, R. Lechan, C. Nicolini, C. R. Abeledo, Richard B. Frankel
Physics
Magnetic hyperfine interactions in (Fe salen C1)2 have been studied using the Mössbauer effect in external magnetic fields up to 80 kOe and for 4.2 ≤ T ≤ 80 °K. The low‐temperature results are adequately described by a simple intramolecular exchange model with J = 7.0 cm−1 and a hyperfine interaction constant of −180 kOe per unit spin. At higher temperature the effective field approximation breaks down. Data for (Fe salen)2O are also briefly reported.
Orbital Ground State Inversion In [Fe(H2O)6](Clo4)2, W. M. Reiff, Richard B. Frankel, C. R. Abeledo
Orbital Ground State Inversion In [Fe(H2O)6](Clo4)2, W. M. Reiff, Richard B. Frankel, C. R. Abeledo
Physics
Mössbauer spectroscopy in external magnetic fields has been used to measure the signs of the principal components of the electric field gradient Vzz in the two forms of [Fe(H2O)6)(Cl04)2. The signs are Vzznegative for low temperature form (A) with quadrupole splitting ΔEA = 3.4 mm/sec, and Vzz positive for high temperature form (B) with ΔEB = 1.4 mm/sec. This implies a trigonally distorted ligand field and the transition (A) → (B) corresponds to compression → elongation with respect to the trigonal axis.
Orbital Ground State Reversal In The High‐Spin Complex Fe(Ii) (N, N′‐Dicyclohexylthiourea)6(Clo4)2, R. Latorre, C. R. Abeledo, Richard B. Frankel, J. A. Costamagna, W. M. Reiff, E. Frank
Orbital Ground State Reversal In The High‐Spin Complex Fe(Ii) (N, N′‐Dicyclohexylthiourea)6(Clo4)2, R. Latorre, C. R. Abeledo, Richard B. Frankel, J. A. Costamagna, W. M. Reiff, E. Frank
Physics
Mössbauer spectroscopy of iron (II)(N, N′‐Dicyclohexylthiourea)6 (ClO4)2 shows the existence of two isomers. At low temperatures (T < 200°K) a form A with quadrupole splitting ΔE = 3.31 mm∕sec is stable. At and above room temperature a form B with ΔE = 1.32 mm∕sec is stable. For 200 °K < T < 300°K both forms are observed with the B∕A ratio increasing with increasing temperature. The values of ΔE are typical of Fe2+ with an orbital singlet and an orbital doublet ground state for A and B, respectively. The isomer shift and magnetic susceptibility results indicate that both …
High Magnetic Field Behavior Of Iron Impurities In Chromium, Richard B. Frankel, N. A. Blum
High Magnetic Field Behavior Of Iron Impurities In Chromium, Richard B. Frankel, N. A. Blum
Physics
Mössbauer measurements in 57Fe in dilute FeCr alloys in external magnetic fields up to 140 kOe are presented. The magnetic hyperfine interactions are compared with results obtained by Herbert, Clark and Wilson and are discussed in terms of a model due to Housley and Dash.
Synthetic Analogs Of The Active Sites Of Iron-Sulfur Proteins. Structure And Properties Of Bis[O-Xylyldithiolato-Μ2-Sulfidoferrate(Iii)], An Analog Of The 2fe-2s Proteins, J. J. Mayerle, Richard B. Frankel, R. H. Holm, James A. Ibers, W. D. Phillips, J. F. Weiher
Synthetic Analogs Of The Active Sites Of Iron-Sulfur Proteins. Structure And Properties Of Bis[O-Xylyldithiolato-Μ2-Sulfidoferrate(Iii)], An Analog Of The 2fe-2s Proteins, J. J. Mayerle, Richard B. Frankel, R. H. Holm, James A. Ibers, W. D. Phillips, J. F. Weiher
Physics
The synthetic analog approach has been applied to a clarification of the active sites of 2Fe-2S* proteins. The compound (Et4N)2[FeS(SCH2)2C6H4]2, derived from o-xylyl-α,α′-dithiol, has been prepared and its structure has been determined by x-ray diffraction. The centrosymmetric anion contains two tetrahedrally coordinated ferric ions bridged by two sulfide ions and separated by 2.70 Å. Comparison of electronic, Mössbauer, and proton magnetic resonance spectra and magnetic susceptibility of the anion with the corresponding properties of the oxidized forms of the proteins reveals …
Antiferromagnetic To Paramagnetic Transition In Fe2+: Mnf2 In External Magnetic Fields, C. R. Abeledo, Richard B. Frankel, M. A. Weber, A. Misetich
Antiferromagnetic To Paramagnetic Transition In Fe2+: Mnf2 In External Magnetic Fields, C. R. Abeledo, Richard B. Frankel, M. A. Weber, A. Misetich
Physics
Mössbauer effect measurements across the antiferromagnetic to paramagnetic phase boundary in Fe2+ : MnF2 in external magnetic fields are reported. From the data, J(Mn-Fe)= -1.7 cm-1. The phase boundary is found to vary as Ho2, as in pure MnF2.
Far Infrared Absportion Of Fe(2+) In Kmgf3, R. B. Frankel, C. R. Abeledo, A. Misetich
Far Infrared Absportion Of Fe(2+) In Kmgf3, R. B. Frankel, C. R. Abeledo, A. Misetich
Physics
Far infrared absorption in cubic KMgF3 doped with Fe2+ is reported . A line is observed at 87cm−1, which is assigned to the (Γ5g → Γ3g, Γ4g) transition in the Fe2+. The reduction in the spin-orbit coupling from the free ion value has been predicted by Ham, Schwarz and O'Brien.