Observations of the electric quadrupole moments of a number of nuclear levels—111Cd (247 keV),115In (ground state),119Sn (24 keV), and121Sb (ground state) —based on the electric field gradients in a series oftrans‐[dimethyl organometallic moieties]

1979 ◽  
Vol 71 (9) ◽  
pp. 3744-3749 ◽  
Author(s):  
T. K. Sham
Keyword(s):  
Electric Field ◽  
Ground State ◽  
Electric Quadrupole ◽  
Quadrupole Moments ◽  
Electric Field Gradients ◽  
Field Gradients ◽  
Nuclear Levels

Effect of ordering on the specific heat of Cu3Au below 3 °K

1968 ◽  
Vol 46 (8) ◽  
pp. 923-927 ◽  
Author(s):  
Douglas L. Martin
Keyword(s):  
Elastic Constant ◽  
Specific Heat ◽  
Electric Quadrupole ◽  
Quadrupole Moments ◽  
Electronic Specific Heat ◽  
Electric Field Gradients ◽  
Specific Heats ◽  
Disordered Lattice ◽  
Field Gradients ◽  
Lattice Specific Heat

Ordering reduces the nuclear, electronic, and lattice specific heats. The change in nuclear specific heat supports the hypothesis that this term in the specific heat arises from the interaction of nuclear electric quadrupole moments with electric field gradients in the disordered lattice. The small (3.5%) change in the electronic specific heat suggests little change in the Fermi surface on ordering. The change in the lattice specific heat is greater than expected from elastic constant measurements on ordered and disordered Cu3Au.

The nuclear quadrupole moment of 69Ga and 115In

2009 ◽  
Vol 87 (7) ◽  
pp. 802-805 ◽  
Author(s):  
Hana Yakobi ◽  
Ephraim Eliav ◽  
Uzi Kaldor
Keyword(s):  
Electric Field ◽  
Fock Space ◽  
Coupling Constants ◽  
Basis Sets ◽  
Coupled Cluster ◽  
Quadrupole Moments ◽  
Electric Field Gradients ◽  
Field Gradients ◽  
Nuclear Quadrupole ◽  
Nuclear Quadrupole Moments

Electric field gradients at the nuclei of gallim and indium are determined by finite field calculations of the atomic energies as functions of the nuclear quadrupole moments. The four-component Dirac–Coulomb–Gaunt Hamiltonian serves as framework, and all electrons are correlated by Fock-space coupled cluster with single and double excitations or by single reference coupled cluster with approximate triples. Large, converged basis sets (e.g., 28s24p20d13f5g4h for In) and virtual spaces are used. Together with experimental nuclear quadrupole coupling constants, known with high precision, the calculated electric field gradients yield the nuclear quadrupole moments. For 69Ga, we get Q = 174(3) mb, in agreement with the earlier 171(2) mb obtained from molecular calculations. The 115In moment is Q = 772(5) mb, considerably lower than the previously accepted 810 mb, and in good agreement with the recent molecular value of 770(8) mb.

Electric Field Gradients Around Point Defects in Metals

1996 ◽  
Vol 51 (5-6) ◽  
pp. 489-505
Author(s):  
Alfred Seeger ◽  
Jörg Ehmann ◽  
Manfred Fähnle
Keyword(s):  
Electric Field ◽  
Ab Initio ◽  
Density Functional ◽  
Local Density ◽  
Energy Levels ◽  
Full Potential ◽  
Good Resolution ◽  
Quadrupole Moments ◽  
Electric Field Gradients ◽  
Field Gradients

The splittings of nuclear energy levels caused by the electric field gradients acting on the quadrupole moments of nuclei in the neighbourhood of atomic defects in cubic metals may serve as ‘‘fingerprints’’ providing us with a unique characterization of these defects. In favourable cases the NQDOR technique (n̲uclear q̲uadrupole d̲ouble r̲esonance) permits sensitive measurements of these splittings with good resolution. The present paper outlines the status of the ab-initio calculation of electric field gradients with emphasis on the theoretical basis (density functional theory with local density approximation) and on the techniques required for handling the specific problems associated with defects. Recent work by the supercell approach on atomic defects in Al and Cu, making use either of the full-potential linearized augmented-plane-wave method or of the ab-initio pseudopotential method, are reported and compared with experiments. The excellent agreement between experiment and theory for the field gradients acting on the nearest-neighbour nuclei of monovacancies in Al demonstrates the reliability and the potential of the theory.

THE ELECTRON SPIN RESONANCE OF Fe+3 IN SINGLE CRYSTALS OF SPODUMENE

1965 ◽  
Vol 43 (12) ◽  
pp. 2262-2275 ◽  
Author(s):  
A. Manoogian ◽  
F. Holuj ◽  
J. W. Carswell
Keyword(s):  
Electron Spin Resonance ◽  
Single Crystals ◽  
Electron Spin ◽  
Ground State ◽  
Electric Quadrupole ◽  
Spin Hamiltonian ◽  
Electric Field Gradients ◽  
Field Gradients ◽  
Spin Resonance ◽  
Quadrupole Resonance

The electron spin resonance (ESR) spectrum of Fe+3 in spodumene, LiAl(SiO3)2, has been investigated at 24 kMc/sec. One set of five "allowed" transitions between the magnetic sublevels of the 6S5/2 ground state has been detected. The following values have been assigned to the parameters occurring in the spin Hamiltonian (eq. (1)) (bnm in gauss): gx = 2.0086 ± 50, gy = 2.0100 ± 50, gx ± 2.0046 ± 25, b20 = −1 430, b22 = −282, b40 = −20, b42 = 108, b44 = −182. Consideration of electric field gradients measured by methods of electric quadrupole resonance and of the orthorhombic parameters b20 and b22 did not lead to a unique assignment of the Fe+3 impurity to one of the two available cationic sites in spodumene.

Electric Quadrupole Interaction at 181Ta in Isostructural Orthorhombic Cu8Hf3 and Cu8Zr3 Compounds

1998 ◽  
Vol 53 (6-7) ◽  
pp. 355-357
Author(s):  
P. Wodniecki ◽  
B. Wodniecka ◽  
A. Kulińska ◽  
A. Z. Hrynkiewicz
Keyword(s):  
Electric Field ◽  
Quadrupole Interaction ◽  
Perturbed Angular Correlation ◽  
Electric Quadrupole ◽  
Correlation Technique ◽  
Interaction Frequency ◽  
Electric Quadrupole Interaction ◽  
Electric Field Gradients ◽  
Field Gradients ◽  
Time Differential

Abstract The quadrupole interaction of 181Ta probes in isostructural Cu8Hf3 and Cu8Zr3 intermetallic compounds was studied in the temperature range 24 K -1100 K with the time-differential perturbed angular correlation technique. Two nonaxial electric field gradients corresponding to two nonequiv-alent hafnium or zirconium sites in the investigated structure were found. A linear decrease in the quadrupole interaction frequency with increase of temperature for the 8(d) sites was evidenced, while the vQ(T) dependence for the 4(c) sites is weaker and has a T3/2 character.

An ab initio Study of the Molecular Electric-field Gradients of the Chlorsilanes

1996 ◽  
Vol 51 (1-2) ◽  
pp. 41-45
Author(s):  
H. U. Suter ◽  
D. M. Maric ◽  
P. F. Meier
Keyword(s):  
Electric Field ◽  
Ab Initio ◽  
Electron Correlation ◽  
Basis Sets ◽  
Quadrupole Moments ◽  
Electric Field Gradients ◽  
Field Gradients ◽  
Extended Basis ◽  
Good Agreement ◽  
Nuclear Quadrupole Moments

Abstract The electric field gradient (EFG) of chlorine in the chlorine containing silanes (SiCl4 , SiCl3H, SiCl2H2 , and SiClH3) was determined by means of ab initio methods and compared to recent experiments from which nuclear quadrupole moments are extracted. A careful estimation of the AO basis sets and the effect of the electron correlation is undertaken. The results showed the importance of the use of extended basis sets in the calculation of EFGs in second row atoms. Good agreement with deviations less than 5% from the experiments was found. The effect of the electron correlation was found to be small.

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