Ethylsulfate Host Lattice Effects in the EPR Spectra of Gd3+ Ions

1972 ◽  
Vol 50 (10) ◽  
pp. 991-1001 ◽  
Author(s):  
H. A. Buckmaster ◽  
R. Chatterjee ◽  
Y. H. Shing
Keyword(s):  
Electric Field ◽  
Ionic Radius ◽  
Spin Hamiltonian Parameter ◽  
Host Lattice ◽  
Epr Spectra ◽  
Optical Data ◽  
Site Symmetry ◽  
Spin Hamiltonian ◽  
Crystalline Electric Field ◽  
Hamiltonian Parameters

Precision measurements and analysis have been made of the 290 °K, 10 GHz EPR spectra of the Gd3+ [4f7, 8S7/2] ion dilutely substituted (~5:103) into the C3h-site symmetry of the lanthanide host lattices Ln(C2H5SO4)3∙9H2O, where Ln ≡ La, Ce, Pr, Nd, Sm, Eu, Tb, Ho, Er, Tm, Yb, and Lu as well as Y which is chemically lanthanide-like. It is found that empirical, linear relationships exist between the magnitude of the Gd3+ spin-Hamiltonian parameter B20 and (i) the ionic radius of the lanthanide host; (ii) the unit cell dimensions of the host lattice; (iii) the molar volume of the host lattice; and (iv) the estimated crystalline potential parameter [Formula: see text]. A similar linear relationship is found between the ionic radius of the lanthanide host and B60 but not B40. These spin-Hamiltonian parameters are related theoretically to the crystalline electric field parameters through the perturbation interactions of the ground state with the excited states. It is concluded from a review of these interactions that the empirical relations reported in this paper cannot be explained using the values of the crystalline electric field parameters calculated from either excited state optical data or lattice summations. The EPR spin-Hamiltonian parameters for Gd3+ in the Y lattice confirm the latter's lanthanide behavior and assign it an effective ionic radius of (0.0896 ± 0.0001) nm which locates it very close to Ho, (0.0894 ± 0.0001) nm, confirming the results of Von Hevesy, Zachariasen et al., and Ketelaar.

E.p.r. and endor of Tb 4+ in thoria

1965 ◽  
Vol 286 (1406) ◽  
pp. 352-365 ◽  
Keyword(s):  
Magnetic Field ◽  
Electric Field ◽  
Electric Field Gradient ◽  
Hyperfine Structure ◽  
Covalent Bonding ◽  
The Other ◽  
Nuclear Moment ◽  
Spin Hamiltonian ◽  
Crystalline Electric Field ◽  
A Value

E.p.r. and endor spectra have been measured in ThO 2 containing Tb 4+ . The crystalline electric field is cubic, and the splittings are very large compared with other S state ions. The values of the parameters in the standard cubic spin-Hamiltonian are: g = 2·0146 ±0·0004, 60 B 4 = —2527·53 ±0·10 Mc/s, 1260 B 6 = —24·84 ± 0·04 Mc/s, A = —73·891 ±0·023 Mc/s, B = + 6·194 ± 0·038 Mc/s, μN ( 159 Tb) = + 1·994 ± 0·004 nuclear magnetons. There are also additional small high-order terms. There are very marked differences between these parameters and those for the other S state ions Gd 3+ and Eu 2+ . In addition to the much larger 60 B 4 , the g value is in excess of the free spin value; at the nucleus, the electrons produce a smaller magnetic field (proportional to A / g 1 ) and a larger electric field gradient (proportional to B / Q ) than they do in Gd 3+ and Eu 2+ . These differences are probably due to covalent bonding. The value of the nuclear moment of 159 Tb has been used to obtain a value of <r -3 > = 8·23 a.u. for Tb 3+ from the known hyperfine structure in Tb 3+ .

EPR Analysis of Copper Exchanged and Encapsulated Copper (SALEN) Complex in Zeolite - Y

1994 ◽  
Vol 368 ◽  
Author(s):  
N Ulagappan ◽  
V Krishnasamy
Keyword(s):  
Copper Complex ◽  
Zeolite Y ◽  
Spin Hamiltonian Parameter ◽  
Epr Spectra ◽  
Spin Hamiltonian ◽  
Salen Complex ◽  
Hamiltonian Parameter

ABSTRACTCopper exchanged and copper-(salen) complex encapsulated in zeolite-Y were prepared. The encapsulaled complex was analysed by TGA, DRS and IR, which confirms the presence of complex in zeolite. Both copper materials were examined by EPR spectra, and the calculated spin-Hamiltonian parameter indicates the copper complex is more covalent in character than NaCu-Y.

CRYSTALLINE ELECTRIC FIELD EFFECTS IN UPd2Al3

1993 ◽  
Vol 07 (01n03) ◽  
pp. 34-37 ◽  
Author(s):  
A. BÖHM ◽  
A. GRAUEL ◽  
N. SATO ◽  
C. SCHANK ◽  
C. GEIBEL ◽  
...  
Keyword(s):  
Magnetic Susceptibility ◽  
Electric Field ◽  
Specific Heat ◽  
Level Scheme ◽  
Heavy Fermion ◽  
Experimental Results ◽  
Site Symmetry ◽  
Crystalline Electric Field ◽  
Electric Field Effects ◽  
Field Effects

The temperature dependencies of the specific heat and the anisotropic magnetic susceptibility of the heavy-fermion superconductor UPd 2 Al 3 show distinct anomalies which can be described by a crystalline electric field (CEF) model for Uranium with hexagonal site symmetry. We find that a CEF-level scheme for the 3 H 4 multiplet ( 5f 2 configuration) implying two low lying singlets surprisingly well fits the experimental results.

EPR Study of VO2+ Doped Diammonium Tricadmium Tetrakis (Sulfate) Pentahydrate [(NH4)2Cd3(SO4)4 ∙ 5H2O] Single Crystals

2010 ◽  
Vol 65 (4) ◽  
pp. 347-352 ◽  
Author(s):  
Ibrahim Kartal ◽  
Bünyamin Karabulut ◽  
Esat Bozkurt
Keyword(s):  
Single Crystals ◽  
Room Temperature ◽  
Epr Spectra ◽  
Spin Hamiltonian ◽  
Axially Symmetric ◽  
Paramagnetic Resonance ◽  
Sulfate Pentahydrate ◽  
Hamiltonian Parameters ◽  
Electron Paramagnetic ◽  
Very High

Electron paramagnetic resonance (EPR) studies are carried out on vanadyl (VO2+) ions in diammonium tricadmium tetrakis (sulfate) pentahydrate single crystals at room temperature. The EPR spectra of a single crystal exhibit resonance signals characteristic to VO2+ ions. The analysis of EPR spectra indicates that the VO2+ ions in single crystals show two magnetically inequivalent VO2+ sites in distinct orientations occupying substitutional positions in the lattice and showing very high angular dependence. They form in octahedral coordination with tetragonal compression with C4v symmetry. The spin Hamiltonian parameters are determined, and these parameters have been used to estimate the bonding coefficients of the VO2+ ion in a diammonium tricadmium tetrakis (sulfate) pentahydrate lattice. The parallel and perpendicular components of axially symmetric g and hyperfine (A) tensors are evaluated and the results are discussed and compared with previous reports.

A study of the host lattice effect in the lanthanide hydroxides. 34 GHz Gd3+ impurity ion EPR spectra at 77 and 294 K

1982 ◽  
Vol 60 (11) ◽  
pp. 1573-1588 ◽  
Author(s):  
V. M. Malhotra ◽  
H. A. Buckmaster
Keyword(s):  
Point Charge ◽  
Ionic Radius ◽  
Host Lattice ◽  
Epr Spectra ◽  
Zero Field ◽  
Nearest Neighbour ◽  
Zero Field Splitting ◽  
Impurity Ions ◽  
Lattice Effect ◽  
Impurity Ion

The 34 GHz EPR spectra of 5-state (4f7, 8S) Gd3+ impurity ions (~1%) in the isostructural [Formula: see text] symmetry Ln(OH)3 host lattice (Ln ≡ La, Sm, Eu, Tb, Ho, Y) have been studied at 77 and 294 K. The expected seven line ΔM = ± 1 spectrum is observed for Ln = La, Eu, Ho, and Y whereas only a single broad transition is observed for Ln ≡ Sm and Tb. The observed values of the zero field splitting (ZFS) parameter B20 as well as the TZFS are found to be related linearly to (i) the ionic radius, (ii) the Ln–O1 distance, and (iii) the Ln–O2 distance where O1 and O2 are the nearest neighbour equatorial and apical oxygens. However, the slopes are opposite to that predicted by a point charge lattice model. This paper discusses (i) the SH parameters, (ii) the host lattice effect, (iii) the ZFS processes, and (iv) the linewidths observed in the Ln(OH)3 host lattice and attempts to explain the observations using the existing theory. It is found that this apparently simple host lattice exhibits complex effects which do not change systematically with the host lanthanide ion, unlike that observed in most other isostructural lanthanide hosts that have been studied using Gd3+ impurity ions.

Epr Spectra of VO2+ Doped in Na2C4H4O6 Single Crystals

2004 ◽  
Vol 59 (10) ◽  
pp. 669-673
Author(s):  
B. Karabulut ◽  
R. Tapramaz ◽  
F. Köksal
Keyword(s):  
Single Crystal ◽  
Single Crystals ◽  
Room Temperature ◽  
Epr Spectra ◽  
Spin Hamiltonian ◽  
Axially Symmetric ◽  
Angular Variation ◽  
Sodium Tartrate ◽  
Hamiltonian Parameters

EPR spectra of VO2+ ions in di-sodium tartrate, [Na2C4H4O6], single crystal and powder spectra have been studied at room temperature. The angular variation of the EPR spectra has shown that three different VO2+ complexes are located in different chemical environments, and each environment contains two magnetically inequvalent sites. The spin Hamiltonian parameters are determined, and these parameters have been used to assess the bonding coefficients of the VO2+ ion in the di-sodium tartrate lattice. The parallel and perpendicular components of axially symmetric g and hyperfine tensors are evaluated. The results are discussed.

The spin-Hamiltonian parameter temperature dependence of the EPR spectra of Gd3+ impurity ions in Y(OH)3 and Eu(OH)3

1984 ◽  
Vol 62 (2) ◽  
pp. 126-133 ◽  
Author(s):  
H. A. Buckmaster ◽  
V. M. Malhotra ◽  
J. M. Boteler
Keyword(s):  
Temperature Variation ◽  
Ion Pairs ◽  
Spin Hamiltonian Parameter ◽  
Linear Functions ◽  
Zero Field ◽  
Spin Hamiltonian ◽  
Zero Field Splitting ◽  
Measurement Interval ◽  
Crystalline Electric Field ◽  
Impurity Ions

The 9.23 GHz electron paramagnetic resonance (EPR) spectrum of ~1% Gd3+ impurity ions in Y(OH)3 and Eu(OH)3 monocrystals has been measured from 11 to 296 K. These spectra have been analyzed using a C3h symmetry, phenomenological spin-Hamiltonian. The temperature variation of the spin-Hamiltonian parameters was fitted to empirical root-mean-square (rms) best-fit expressions. It was found that the g values are linear functions of the temperature and that the nearest neighbour (nn) exchange interaction, Jnn = +0.23(5) cm−1 for (Gd3+−Eu3+) ion pairs, can be estimated from the single ion data. This is in satisfactory agreement with Jnn = +0.06(9) cm−1 obtained from ion pair data. The temperature variation of the zero field splitting (ZFS) parameters B20 and B40was found to fit cubic expressions over the temperature measurement interval and the magnitude of B20 increased as the temperature increased, corroborating the earlier conclusion that the host lattice effect in the Ln(OH)3 series cannot be explained using a point charge model for the crystalline electric field.

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