Computer simulations of Mössbauer spectra for an effective spin S= Hamiltonian

Münick, E.; Groves, J.L.; Tumolillo, Thomas A.; Debrunner, Peter G.

doi:10.1016/0010-4655(73)90102-1

Cited by 39 publications

(15 citation statements)

References 6 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The Mössbauer spectra were collected on constant acceleration instruments at temperatures between 2 and 150 K in applied external fields up to 8 T. Simulations of spectra were generated using WMOSS (WEB Research, Edina, MN) as well as a modified version of SPHMOSS (Sp in H amiltonian Möss bauer ) 19. Isomer shifts are reported relative to iron metal foil at room temperature.…”

Section: Methodsmentioning

confidence: 99%

Mössbauer, Electron Paramagnetic Resonance, and Magnetic Susceptibility Studies on Members of a New Family of Cyano-Bridged 3d-4f Complexes. Demonstration of Anisotropic Exchange in a Fe−Gd Complex

Stoian

Paraschiv²,

Kiritsakas³

et al. 2010

Inorg. Chem.

View full text Add to dashboard Cite

The synthesis and crystallographic characterization of a new family of M(μ-CN)Ln complexes are reported. Two structural series have been prepared by reacting in water rare earth nitrates (Ln III = La, Pr, Nd, Sm, Eu, Gd, Dy, Ho) with K 3 [M(CN) [CoGd] 10). The hexamethylenetetramine molecules contribute to the stabilization of the crystals by participating in an extended network of hydrogen bond interactions. In both series the aqua ligands are hydrogen bonded to the nitrogen atoms from both the terminal CN groups and the hmt molecules. The [FeGd] complex has been analyzed with 57 Fe Mössbauer spectroscopy, EPR, and magnetic susceptibility measurements. We have also analyzed the [FeLa] complex, in which the paramagnetic Gd III is replaced by diamagnetic La III , to obtain information about the low-spin Fe III site that is not accessible in the presence of a paramagnetic ion at the complementary site. For the same reason, the [CoGd] complex, containing diamagnetic Co III , was studied with EPR and magnetic susceptibility measurements, which confirmed the S = 7/2 spin of Gd III . Prior knowledge about the paramagnetic sites in [FeGd] allows a detailed analysis of the exchange interactions between them. In particular, the question of whether the exchange interaction in [FeGd] is isotropic or anisotropic has been addressed. Standard variable-temperature magnetic susceptibility measurements provide only the value for a linear combination of J x , J y , and J z but contain no information about the values of the individual exchange parameters J x , J y , and J z . In contrast, the spin-Hamiltonian analysis of the variable-field, variable-temperature Mössbauer spectra reveals an exquisite sensitivity on the anisotropic exchange parameters. Analysis of these dependencies in conjunction with adopting the g-values obtained for [FeLa], yielded the values J x = Ŝ 1 · J · Ŝ 2 +0.11 cm −1 , J y = +0.33 cm −1 , and *To whom correspondence should be addressed emunck@cmu.edu; marius.andruh@dnt.ro; eb7g@andrew.cmu.edu. Supporting Information Available Details of the analysis of the magnetic susceptibilities, an explicit derivation of eq 1 as well as a proof for the validity of the subtraction method in the analysis of χT vs. T of [FeGd] are presented. Complete crystallographic data, structure, solution and refinement are available. This material is available free of charge via internet from http://pubs.acs.org. NIH Public AccessAuthor Manuscript Inorg Chem. Author manuscript; available in PMC 2011 April 5. NIH-PA Author ManuscriptNIH-PA Author Manuscript NIH-PA Author Manuscript J z = +1.20 cm −1 (convention). The consistency of these results with magnetic susceptibility data is analyzed. The exchange anisotropy is rooted in the spatial anisotropy of the low-spin Fe III ion. The condition for anisotropic exchange is the presence of low-lying orbital excited states at the ferric site that (i) effectively interact through spin-orbit coupling with the orbital ground state and (ii) have an exchange parameter with t...

show abstract

Section: Methodsmentioning

confidence: 99%

Mössbauer, Electron Paramagnetic Resonance, and Magnetic Susceptibility Studies on Members of a New Family of Cyano-Bridged 3d-4f Complexes. Demonstration of Anisotropic Exchange in a Fe−Gd Complex

Stoian

Paraschiv²,

Kiritsakas³

et al. 2010

Inorg. Chem.

View full text Add to dashboard Cite

show abstract

“…Zero-field spectra were analyzed with a Lorentzian leastsquare fitting computer routine. 42 Magnetically resolved spectra were analyzed with a generalized version of the program described by Münck and co-workers 33 in the effective representation and by a code that diagonalizes eq 2 in the intrinsic representation.…”

Section: Methodsmentioning

confidence: 99%

Mössbauer Spectroscopy of the Spin-Coupled Fe³⁺−Fe²⁺ Center of Reduced Uteroferrin

Rodriguez

Xia

et al. 1996

J. Phys. Chem.

View full text Add to dashboard Cite

The mixed valence active center of the diiron-oxo protein uteroferrin (Ufr), a porcine purple acid phosphatase, has been analyzed by Mössbauer spectroscopy. Low and high magnetic field spectra are consistent with an antiferromagnetically spin-coupled center. Theoretical spectra that simulate experimental data have been calculated by diagonalizing the spin Hamiltonian H )Here the subscripts 1 and 2 refer to Fe 3+ (S 1 ) 5/2) and Fe 2+ (S 2 ) 2), respectively. For T e 4.2 K, both irons exhibit resolved magnetic hyperfine splittings which depend on the direction and magnitude of the external field, and the static limit of H applies. For T g 100 K, the spin fluctuations are fast and pure quadrupole doublets are observed unless strong fields are applied. In Ufr, the dominant isotropic exchange is strongly perturbed by the zero field splitting (ZFS). We have also calculated the EPR g eff tensor by diagonalizing the electronic terms of H. Our work confirms the claim (Sage, J. T.; et al. J. Am. Chem. Soc. 1989, 111, 7239) that the anisotropy of g eff arises from the admixture of higher spin manifolds to the S eff ) 1 / 2 ground state by the ZFS. In order to find a solution to the Hamiltonian, we searched in its large parameter space with a genetic algorithm. This highly effective searching procedure allowed us to find an optimal parameter set that simultaneously reproduces Mössbauer spectra and EPR g values. The strategies employed for the search in the parameter space of H are discussed. We have determined the exchange constant J ) 34.7 cm -1 , ZFS parameters D 1 ) -0.10 cm -1 , E 1 ≈ 0, D 2 ) +10.81 cm -1 , and E 2 ) +3.17 cm -1 , and hyperfine tensors ã 1 /g n n ) -(21.4,21.2,17.8) T and ã 2 /g n n ) -(15.2,12.2,14.1) T. We have also interpreted the 4.2 K spectra with an effective S eff ) 1 / 2 Hamiltonian for the ground state and determined effective hyperfine tensors Ã 1 eff /g n n ) -(45.6,64.1,31.3) T and Ã 2 eff /g n n ) +(11.4,24.9,16.7) T. For Fe 2+ , the ZFS and the electric and magnetic hyperfine interactions were consistent with the presence of axial and rhombic distortions of the dominant octahedral electrostatic potential. The principal axes of the orthorhombic field, which are rotated by 45°about the z axis of the octahedral field, defined an orbital ground state for Fe 2+ of |x 2 -y 2 〉 symmetry with some |z 2 〉 admixture, consistent with the sign of the electric field gradient. Knowledge of the orbital ground state has allowed us to estimate the intrinsic Fermi contact, orbital, and dipolar hyperfine tensors for Fe 2+ .

show abstract

“…al. [26] Assuming fast relaxation and using g xx ϭ 1.3, g yy ϭ 1.3, and g zz ϭ 4.4, [12] ∆E Q ϭ eQV ζζ ϭ Ϫ0.17 mm/s, η ϭ 0, A xx /(g N µ N ) ϭ Ϫ110 kG, A yy /(g N µ N ) ϭ Ϫ110 kG, and A zz /(g N µ N ) ϭ ϩ820 kG, the calculated simulations are plotted on the experimental spectra ( Figure 11). Non-zero values of α, β, and γ were considered but did not Figure 11.…”

Section: Mössbauer Spectroscopymentioning

confidence: 99%

Crystal Structure and Magnetic Behavior of the Decamethylferrocenium and Decamethylchromocenium Salts of Bis(ethylenedithiolato)nickel, [M(Cp)2][Ni(edt)2] − Magnetic Anisotropy and Metamagnetic Behavior of [Fe(Cp)2][Ni(edt)2]

Gama

Belo

Rabaça

et al. 2000

Eur. J. Inorg. Chem.

View full text Add to dashboard Cite

Computer simulations of Mössbauer spectra for an effective spin S= Hamiltonian

Cited by 39 publications

References 6 publications

Mössbauer, Electron Paramagnetic Resonance, and Magnetic Susceptibility Studies on Members of a New Family of Cyano-Bridged 3d-4f Complexes. Demonstration of Anisotropic Exchange in a Fe−Gd Complex

Mössbauer, Electron Paramagnetic Resonance, and Magnetic Susceptibility Studies on Members of a New Family of Cyano-Bridged 3d-4f Complexes. Demonstration of Anisotropic Exchange in a Fe−Gd Complex

Mössbauer Spectroscopy of the Spin-Coupled Fe³⁺−Fe²⁺ Center of Reduced Uteroferrin

Crystal Structure and Magnetic Behavior of the Decamethylferrocenium and Decamethylchromocenium Salts of Bis(ethylenedithiolato)nickel, [M(Cp)2][Ni(edt)2] − Magnetic Anisotropy and Metamagnetic Behavior of [Fe(Cp)2][Ni(edt)2]

Contact Info

Product

Resources

About

Computer simulations of Mössbauer spectra for an effective spin S= Hamiltonian

Cited by 39 publications

References 6 publications

Mössbauer, Electron Paramagnetic Resonance, and Magnetic Susceptibility Studies on Members of a New Family of Cyano-Bridged 3d-4f Complexes. Demonstration of Anisotropic Exchange in a Fe−Gd Complex

Mössbauer, Electron Paramagnetic Resonance, and Magnetic Susceptibility Studies on Members of a New Family of Cyano-Bridged 3d-4f Complexes. Demonstration of Anisotropic Exchange in a Fe−Gd Complex

Mössbauer Spectroscopy of the Spin-Coupled Fe3+−Fe2+ Center of Reduced Uteroferrin

Crystal Structure and Magnetic Behavior of the Decamethylferrocenium and Decamethylchromocenium Salts of Bis(ethylenedithiolato)nickel, [M(Cp*)2][Ni(edt)2] − Magnetic Anisotropy and Metamagnetic Behavior of [Fe(Cp*)2][Ni(edt)2]

Contact Info

Product

Resources

About

Mössbauer Spectroscopy of the Spin-Coupled Fe³⁺−Fe²⁺ Center of Reduced Uteroferrin

Crystal Structure and Magnetic Behavior of the Decamethylferrocenium and Decamethylchromocenium Salts of Bis(ethylenedithiolato)nickel, [M(Cp)2][Ni(edt)2] − Magnetic Anisotropy and Metamagnetic Behavior of [Fe(Cp)2][Ni(edt)2]