ELECTRON SPIN RESONANCE OF Fe+3 IN CORDIERITE

1966 ◽  
Vol 44 (11) ◽  
pp. 2749-2755 ◽  
Author(s):  
N. E. Hedgecock ◽  
S. C. Chakravartty
Keyword(s):  
Electron Spin Resonance ◽  
Electron Spin ◽  
Room Temperature ◽  
Esr Spectra ◽  
Orthorhombic Symmetry ◽  
Zero Field ◽  
Spin Hamiltonian ◽  
Zero Field Splitting ◽  
Field Splitting ◽  
Spin Resonance

ESR spectra of Fe+3 located at one of the aluminium sites in cordierite have been investigated at X- and K-band frequencies at room temperature. The spectra exhibit large zero-field splitting and have been fitted to a spin Hamiltonian of orthorhombic symmetry, having constants b20 = 14.6 ± 0.1 kG, b22 = 8.5 ± 0.1 kG, and isotropic g = 2.004 ± 0.002.

ESR SPECTRA OF Fe+3 IN SINGLE CRYSTALS OF ANDALUSITE

1966 ◽  
Vol 44 (3) ◽  
pp. 509-523 ◽  
Author(s):  
F. Holuj ◽  
J. R. Thyer ◽  
N. E. Hedgecock
Keyword(s):  
Single Crystals ◽  
Room Temperature ◽  
Esr Spectra ◽  
Zero Field ◽  
Spin Hamiltonian ◽  
Zero Field Splitting ◽  
Field Splitting ◽  
K Band

ESR spectra of Fe+3 in andalusite have been investigated at X- and K-band frequencies at room temperature. They have been interpreted on the assumption that Fe+3 occupies the two inequivalent Al+3 sites in andalusite. The spectra show large zero-field splitting. The constants of the conventional orthorhombic spin Hamiltonian which fit the spectra are as follows: for site I: b20 = 15.0 ± 0.1 kG, b22 = 5.0 ± 0.1 kG, and isotropic g = 2.001 ± 0.002; for site II: b20 = 20.1 ± 0.1 kG, b22 = 0.075 ± 0.010 kG, and isotropic g = 2.004 ± 0.0005. A study of the intensities of ESR signals due to site I follow a pattern predicted by theory. The implications of these results are considered briefly.

Electron spin resonance studies of 53Cr3+ and VO2+ ions in AlCl3∙6H2O

1976 ◽  
Vol 54 (2) ◽  
pp. 217-222 ◽  
Author(s):  
K. Pack ◽  
A. Manoogian
Keyword(s):  
Electron Spin Resonance ◽  
Electron Spin ◽  
Double Resonance ◽  
Zero Field ◽  
Spin Hamiltonian ◽  
Zero Field Splitting ◽  
Electron Nuclear Double Resonance ◽  
Spin Resonance ◽  
Impurity Doping ◽  
Static Distortion

The electron-nuclear double resonance (ENDOR) of 53Cr3+ ions and the electron spin resonance (ESR) of VO2+ ions are studied in single crystals of AlCl3∙6H2O. The ENDOR measurements are done at 4.2 K while the resonance of VO2+ is studied at room temperature. The sign of the Cr3+ spin Hamiltonian zero field splitting parameter D is found to be negative while the anisotropic hyperfine parameter has the relation A < B. It is concluded that the octahedron of waters surrounding the chromium ion is trigonally compressed. The value of the 53Cr3+ quadrupole interaction parameter Q′ is nearly the same as that found previously in the cesium alums even though the D value is considerably smaller in AlCl3∙6H2O. This indicates that Q′ is independent of D at 4.2 K in these salts and the expected proportionality [Formula: see text], which is based on a purely static distortion for the octahedron of waters surrounding the Cr3+ ion, does not hold. The resonance results for VO2+ show the nature of the two inequivalent but otherwise similar Al∙6H2O complexes in the unit cell. The VO2+∙5H2O complexes associated with the two types of aluminum sites are found to be rotated relative to each other by an angle of 33 ± 3° in the plane perpendicular to the crystal c axis. A comparison of the spin Hamiltonian parameters of VO2+ and 53Cr3+ in AlCl3∙6H2O with those obtained previously in CsAl alum indicates that the Al∙6H2O complexes in CsAl alum are more susceptible to distortion upon impurity doping than are those in AlCl3∙6H2O.

The electron spin resonance of Mn2+ in tremolite

1968 ◽  
Vol 46 (2) ◽  
pp. 129-133 ◽  
Author(s):  
A. Manoogian
Keyword(s):  
Electron Spin Resonance ◽  
Angular Dependence ◽  
Electron Spin ◽  
Room Temperature ◽  
Microwave Frequency ◽  
Orthorhombic Symmetry ◽  
Spin Hamiltonian ◽  
Frequency Range ◽  
Line Intensities ◽  
Spin Resonance

The electron spin resonance of Mn2+ ion impurities in natural crystals of tremolite, 2(H2Ca2Mg5-(SiO3)8), was studied in the 9.2 GHz microwave frequency range, and at room temperature. The work was done on two crystals of tremolite containing different concentrations of Mn2+. In each case only one magnetic complex of Mn2+ was found. The resonance lines are characterized by a strong angular dependence of the line intensities, and this is coupled with the appearance of many forbidden lines of Mn2+. The resonance lines of the allowed transitions were fitted to a spin Hamiltonian of orthorhombic symmetry.

Electron spin resonance of Mn2+ impurities in morinite

1969 ◽  
Vol 47 (17) ◽  
pp. 1869-1875 ◽  
Author(s):  
A. Manoogian ◽  
Y. Hsu
Keyword(s):  
Electron Spin Resonance ◽  
Electron Spin ◽  
Room Temperature ◽  
Microwave Frequency ◽  
Heat Treating ◽  
Orthorhombic Symmetry ◽  
Spin Hamiltonian ◽  
Frequency Range ◽  
Spin Resonance ◽  
Impurity Ions

The electron spin resonance of Mn2+ impurity ions in natural crystals of morinite, Ca4Na2Al4(F, OH)10(PO4)4∙3H2O, was studied in the 9.4 GHz microwave frequency range and at room temperature. A single magnetic complex was found and the resonance lines were characterized by strong splittings due to superhyperfine interactions with ligand nuclei. The resonance lines were fitted to a spin Hamiltonian of orthorhombic symmetry and the following parameters were determined: gz = 2.0014 ± 0.0005, gy = 2.0017 ± 0.0010, b2°= 166.8 ± 1.5, b22 = 69.1 ± 1.5, b40 = −0.17 ± 0.10, A = 98.2 ± 1.0, and B = C = 99.7 ± 1.5. The values of bnm, A, B, and C are in gauss, and the signs are relative. By heat-treating powdered samples of morinite to a temperature greater than 400 °C, it was shown that the morinite changed to apatite, 2[Ca5(PO4)3(F, OH)].

scholarly journals A new method for determining the concentration of vanadyl ions in clays

2011 ◽  
Vol 62 (2) ◽  
pp. 181-186 ◽  
Author(s):  
Pavle Premović ◽  
Budimir Ilić ◽  
Dragan Đorđević
Keyword(s):  
Electron Spin Resonance ◽  
Electron Spin ◽  
Room Temperature ◽  
Esr Spectra ◽  
New Method ◽  
Simple Method ◽  
Routine Work ◽  
Spin Resonance ◽  
Resonance Data ◽  
Electron Spin Resonance Data

A new method for determining the concentration of vanadyl ions in claysA novel and simple method for quantitatively determining the concentration of vanadyl ions in clays using electron spin resonance data has been developed. Several vanadyl standards with concentrations between 200-1000 ppm were prepared in a mixture of glycerol and kaolinite (KGa-2). The anisotropic electron spin resonance (ESR) spectra were recorded at room temperature, and the specific intensity of the line (attributed to nuclear spin m = -5/2||) was determined. For vanadyl concentrations between 50 ppm and 200 ppm, the standards must be prepared by mixing kaolinite with known vanadyl content (FBT2A-03) and kaolinite (GB1) containing no vanadyl. The method is applicable without modification to other clays and clay-rich sediments containing vanadyl ions. The whole procedure is very suitable for routine work.

Electron Spin Resonance of Cr3+ in K1–xTlxAl(SO4)2 · 12 H2O

2003 ◽  
Vol 58 (5-6) ◽  
pp. 303-305 ◽  
Author(s):  
V. K. Jain
Keyword(s):  
Electron Spin Resonance ◽  
Electron Spin ◽  
Metal Ion ◽  
Zero Field ◽  
Zero Field Splitting ◽  
Trivalent Metal ◽  
Zero Field Splitting Parameter ◽  
Monovalent Ions ◽  
Spin Resonance ◽  
Splitting Parameter

The electron spin resonance (ESR) of Cr3+ in K1−xTlxAl(SO4)2·12H2O has been studied at 300 K and 9.45 GHz. The ESR spectrum for x between 30 and 90% shows several chromium complexes. The variation of the zero-field splitting parameter D suggests that monovalent ions play an important role in the trigonal distortion of the water octahedron around the trivalent metal ion in alums. - PASC: 76.30 F.

scholarly journals Electron Spin Resonance Measurement with Microinductor on Chip

2011 ◽  
Vol 2011 ◽  
pp. 1-3
Author(s):  
Akio Kitagawa
Keyword(s):  
Electron Spin Resonance ◽  
Electron Spin ◽  
Room Temperature ◽  
Near Field ◽  
Esr Spectra ◽  
Ethanol Solution ◽  
Spin Resonance ◽  
On Chip ◽  
Processing Circuit ◽  
Probe Head

The detection of radicals on a chip is demonstrated. The proposed method is based on electron spin resonance (ESR) spectroscopy and the measurement of high-frequency impedance of the microinductor fabricated on the chip. The measurement was by using a frequency sweep of approximately 100 MHz. The ESR spectra of di(phenyl)-(2,4,6-trinitrophenyl)iminoazanium (DPPH) dropped on the microinductor which is fabricated with CMOS 350-nm technology were observed at room temperature. The volume of the DPPH ethanol solution was 2 μL, and the number of spins on the micro-inductor was estimated at about 1014. The sensitivity is not higher than that of the standard ESR spectrometers. However, the result indicates the feasibility of a near field radical sensor in which the microinductor as a probe head and ESR signal processing circuit are integrated.

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