Electron-Paramagnetic-Res Spectroscopy of a Trigonal Prismatic Vanadium Cage Complex - [1,8-Diammonio-3,6,10,13,16,19-hexaazabicyclo-[6.6.6]icosanato(3,6)vanadium(IV)](4+)

1986 ◽  
Vol 39 (7) ◽  
pp. 1029 ◽  
Author(s):  
P Comba ◽  
AM Sargeson
Keyword(s):  
Ground State ◽  
Poly Vinyl Alcohol ◽  
Large Temperature ◽  
Fluid Solution ◽  
Spin Hamiltonian ◽  
Metal Centre ◽  
Cage Complex ◽  
Hamiltonian Parameters ◽  
Electron Paramagnetic ◽  
Trigonal Prismatic

An e.p.r . study of the cage complex [VIVdi(amH)sar-2H]4+ gives spin Hamiltonian parameters gX 1.974, gy 1.967, gZ 1.991, giso 1.977, AX 92×10-4 cm-1, Ay 100×10-4 cm-1, AZ 13×10-4 cm-1, Aiso 68×10-4 cm-1, viz. gX ≈ gy < gZ ≈ 2.0 and AX ≈ Ay > AZ. This is consistent with the metal centre approaching a trigonal prismatic environment and a 2A1 (D3) ground state, viz. ...d1/z2. Comparison of the spin Hamiltonian parameters from measurements in frozen and fluid solution, poly(vinyl alcohol) films and dilute powder [VIVdi(amH)sar-2H]4+ doped into the lattice of the protonated ZnII salt over a large temperature range indicates that the structures in solution and in the solid state are virtually identical. The results are discussed in relation to the known structure of the ion in the lattice [vIVdi(amH)sar -2H](S2O6)2, the sites of deprotonation of the coordinated amines and in relation to the trigonal and small rhombic distortions of the complex.

Electron Paramagnetic Resonance of Cu2+ Doped Na2 HAsO4·7H2O Single Crystals

1998 ◽  
Vol 53 (9) ◽  
pp. 779-782
Author(s):  
F. Köksal ◽  
İ. Kartal ◽  
A. Gençten
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Single Crystals ◽  
Ground State ◽  
Room Temperature ◽  
Charge Compensation ◽  
Distorted Octahedron ◽  
Spin Hamiltonian ◽  
Paramagnetic Resonance ◽  
Hamiltonian Parameters ◽  
Electron Paramagnetic

Abstract The electron paramagnetic resonance spectra of Cu2+ doped Na2HAsO4 ·7H2O single crystals were studied at room temperature. The results indicate the substitutional entrance of Cu2+ in two magnetically inequivalent Na+ sites. Charge compensation is supposed to be fulfilled by proton vacancies. The spin Hamiltonian parameters were determined. The ground state for Cu2+ seems to indicate the dominance of the dz² orbital and therefore a compression of the distorted octahedron along its C4v axis.

Investigation of the Spin Hamiltonian Parameters and the Local Structure of Two Ni3+ Centers in KTaO3

2004 ◽  
Vol 59 (4-5) ◽  
pp. 203-208 ◽  
Author(s):  
Shao-Yi Wu ◽  
Hui-Ning Dong ◽  
Wang-He Wei
Keyword(s):  
Covalent Bonding ◽  
Interstitial Oxygen ◽  
Nearest Neighbour ◽  
Spin Hamiltonian ◽  
Electron Paramagnetic Resonance Data ◽  
Paramagnetic Resonance ◽  
Local Structures ◽  
Resonance Data ◽  
Hamiltonian Parameters ◽  
Electron Paramagnetic

The spin Hamiltonian anisotropic g factors g∥ and g⊥ and the local structures of the Ni3+ centers I and II in KTaO3 are theoretically investigated by using the perturbation formulas of the spin Hamiltonian parameters for 3d7 ions in tetragonally distorted octahedrons and dodecahedrons. By analyzing the electron paramagnetic resonance data of the studied systems, the centers I and II can be attributed to Ni3+ ions occupying octahedral Ta5+ (associated with a nearest-neighbour oxygen vacancy VO along the C4 axis) and the dodecahedral K+ (associated with a nearest-neighbour interstitial oxygen OI along the C4 axis) sites, respectively. Based on these studies, it is found that at the center I the impurity Ni3+ is displaced away from VO by ΔZI ≈ −0.31(2) Å along the C4 axis. At the center II a large off-center displacement, ΔZII ≈ 1.12(2) Å , towards the OI along the C4 axis is obtained, due to Ni3+-OI covalent bonding.

Epr of Mn2+ in Ni(CH3COO)2 4H2O and K2 Ni(SO4)2 6H2O

1980 ◽  
Vol 3 ◽  
Author(s):  
Sushil K. Misra ◽  
M. Jalochowski
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Magnetic Properties ◽  
Transition Temperature ◽  
Single Crystals ◽  
Liquid Helium ◽  
Liquid Nitrogen ◽  
Spin Hamiltonian ◽  
Paramagnetic Resonance ◽  
Hamiltonian Parameters ◽  
Electron Paramagnetic

ABSTRACTThe technique of electron paramagnetic resonance has been applied to study the magnetic properties of nickel acetate and nickel potassium tutton salt single crystals, using Mn2+ ion as probe. From the values of spin Hamiltonian parameters and linewidths at room, liquid nitrogen and liquid helium temperatures it is concluded that these crystals do not become magnetically ordered as the temperature is lowered to 3.2K, and thus the transition temperature, below which the crystal would order either ferromagnetically, or antiferromagnetically, for these crystals, should be below 3.2K.

EPR AND OPTICAL STUDIES OF VANADYL IONS IN ALKALI LEAD BOROTELLURITE GLASSES

2005 ◽  
Vol 19 (13n14) ◽  
pp. 643-653 ◽  
Author(s):  
R. P. SREEKANTH CHAKRADHAR ◽  
G. SIVARAMAIAH ◽  
J. LAKSHMANA RAO ◽  
N. O. GOPAL
Keyword(s):  
Optical Absorption ◽  
Molecular Ions ◽  
Tetragonal Symmetry ◽  
Spin Hamiltonian ◽  
Paramagnetic Resonance ◽  
Fermi Contact Interaction ◽  
Fermi Contact ◽  
Hamiltonian Parameters ◽  
Electron Paramagnetic ◽  
Boltzmann Law

Electron Paramagnetic Resonance (EPR) and optical absorption spectra of VO 2+ ions in different alkali lead borotellurite glasses have been studied. The spin-Hamiltonian parameters (g and A), bonding parameter [Formula: see text] and Fermi contact interaction parameter k have been calculated. The values of spin-Hamiltonian parameters confirm that the vanadyl ions are present in the glasses as VO 2+ molecular ions in an octahedral site with a tetragonal compression. The number of spins (N) participating in resonance is calculated as a function of temperature (123–393 K) for 9 mol% of VO 2+ ions in lithium lead borotellurite glass sample. It is observed that N obeys the Boltzmann law. From EPR data, the paramagnetic susceptibility (χ) is calculated at various temperatures and the Curie constant has been evaluated from 1/χ–T graph. The optical absorption spectrum exhibits two bands characteristic of VO 2+ ions in tetragonal symmetry. The band gap (E opt ) and the Urbach energies (ΔE) have been determined from the ultraviolet absorption edges and are found to be dependant on the size of the alkali ion. The theoretical values of optical basicity (Λ th ) of these glasses have also been evaluated.

EPR Studies of Mn2+-Doped Diammonium Hexaaqua Magnesium(II) Sulfate

2006 ◽  
Vol 61 (12) ◽  
pp. 683-687 ◽  
Author(s):  
Ram Kripal ◽  
Ashutosh Kumar Shukla
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Fine Structure ◽  
Single Crystals ◽  
Room Temperature ◽  
Spin Hamiltonian ◽  
Epr Spectrum ◽  
Paramagnetic Resonance ◽  
X Band ◽  
Hamiltonian Parameters ◽  
Electron Paramagnetic

Electron paramagnetic resonance (EPR) studies of Mn2+ impurity in single crystals of diammonium hexaaqua magnesium(II) sulfate have been carried out at 9.3 GHz (X-band) at room temperature. The EPR spectra exhibit a group of five fine structure transitions. The spin-Hamiltonian parameters were determined. Mn2+ enters the lattice interstitially. The EPR spectrum of a powder sample supports the data obtained by single crystal studies. - PACS number: 76.30

EPR Studies of VO2+ in Ba(ClO4) 2 ・3H2O Single Crystals

1997 ◽  
Vol 52 (12) ◽  
pp. 849-854 ◽  
Author(s):  
Metin Yavuz ◽  
Hüseyin Kalkan ◽  
Ahmet Bulut ◽  
Şehriman Atalay ◽  
Emin Öztekin
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Single Crystal ◽  
Single Crystals ◽  
Axial Symmetry ◽  
Powder Sample ◽  
Spin Hamiltonian ◽  
Paramagnetic Resonance ◽  
Vanadyl Ion ◽  
Hamiltonian Parameters ◽  
Electron Paramagnetic

The results of an electron paramagnetic resonance (EPR) study of vanadyl ion VO2+ doped in single crystals of Ba(ClO4)2 - 3 H2O are reported. The spectra indicated the presence of two substitutional and interstitial sites depending on the orientation. The spin-Hamiltonian parameters were determined from single crystal and powder EPR data. These parameters were found to be axial symmetric for the powder sample, whereas they showed deviations from axial symmetry for the single crystal

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