Calculation of the electric field gradients, generalized Sternheimer shielding constants, and electric‐field‐gradient polarizabilities for ten small molecules

1994 ◽  
Vol 100 (9) ◽  
pp. 6628-6632 ◽  
Author(s):  
David M. Bishop ◽  
Sl/awomir M. Cybulski
Keyword(s):  
Electric Field ◽  
Electric Field Gradient ◽  
Small Molecules ◽  
Field Gradient ◽  
Electric Field Gradients ◽  
Field Gradients ◽  
Shielding Constants

Electric Field Gradients in Alkali Halide Molecules

1974 ◽  
Vol 52 (11) ◽  
pp. 2143-2156 ◽  
Author(s):  
Jean-Pierre Laplante ◽  
Andre D. Bandrauk
Keyword(s):  
Electric Field ◽  
Electric Field Gradient ◽  
Field Gradient ◽  
Alkali Halide ◽  
Electric Field Gradients ◽  
Calculated Density ◽  
Proper Understanding ◽  
Hartree Fock ◽  
Field Gradients ◽  
Classical Models

The electric field gradient q has been calculated from Hartree–Fock wavefunctions for the molecules LiF, LiCl, LiBr, NaF, NaCl, NaBr, KF, and KCl. It is found that σ and π electrons behave quite differently. Exchange distortions are of great importance for a proper understanding of σ contributions to q. Polarizations of π electrons into the bonding region are also considerable. These effects are responsible for failures of classical models and are further discussed using calculated density difference diagrams.

Electric Field Gradients for Small Antimony Based Zintl Clusters from Hartree-Fock Investigations

1996 ◽  
Vol 51 (5-6) ◽  
pp. 557-559
Author(s):  
F. Hagelberg ◽  
T.P. Das ◽  
K. G. Weil
Keyword(s):  
Electric Field ◽  
Electric Field Gradient ◽  
Field Gradient ◽  
Structural Changes ◽  
Electric Field Gradients ◽  
Hartree Fock ◽  
Field Gradients ◽  
Valence Electrons ◽  
Zintl Clusters

Abstract Electric Field Gradient (EFG) calculations have been carried out for Antimony based clusters with 20 and with 22 valence electrons. It is shown that EFGs are very sensitive to structural changes of the clusters under study. This feature can be used to demonstrate the validity of the Zintl-Klemm-Busmann principle for these systems through EFG determinations.

F-Tensor Coefficients in Electric Field Gradient Calculations for Non-Coulombic Potentials

1996 ◽  
Vol 51 (5-6) ◽  
pp. 554-556
Author(s):  
M.J. Ponnambalam
Keyword(s):  
Electric Field ◽  
Electric Field Gradient ◽  
Field Gradient ◽  
Electric Field Gradients ◽  
Cubic Crystals ◽  
Field Gradients

Abstract The F-tensor coefficients are useful in evaluating the stress-induced electric field gradients in cubic crystals. These coefficients are derived for the non-Coulombic inter-atomic potentials Gr-n and Ge-br . Interesting differences are pointed out between these results and those for Coulombic potentials.

Field-Swept NMR Spectra of 11B in Pyrex Glass and 93Nb in NbN Perturbed by Quadrupole Interaction

1998 ◽  
Vol 53 (6-7) ◽  
pp. 309-313 ◽  
Author(s):  
H. Yoshida ◽  
H. Nishihara ◽  
S. Yokota ◽  
M. Ohyanagi ◽  
T. Nakaoki
Keyword(s):  
Electric Field ◽  
Electric Field Gradient ◽  
Field Gradient ◽  
Quadrupole Interaction ◽  
Pyrex Glass ◽  
Electric Field Gradients ◽  
Field Gradients ◽  
High Temperature Synthesis ◽  
High Resolution Nmr ◽  
Quadrupole Effect

Abstract NMR experiments of 11B by both field-swept and high-resolution NMR are reported to probe the electric field gradient at boron sites and its distribution in Pyrex glass. Both spectra are successfully interpreted with the same set of parameters. It is stressed that field-swept NMR experiments to observe total powder spectrum can be helpful to get information on electric field gradients and asymmetry pa-rameters if there exist many nonequivalent sites of atoms, since satellite transitions are affected by the larger first-order quadrupole effect. Field-swept NMR of 93Nb in superconducting NbN powder, prepared by self-propagating high-temperature synthesis, is also reported. A very broad field-swept spectrum disturbed by quadrupole interaction has been observed. The spectrum is simulated by assuming distributions in electric field gradient and Knight shift at Nb sites. It is stressed that a combination of experiments at separated frequencies is important.

ELECTRIC FIELD GRADIENTS IN SEMICONDUCTORS AND INSULATORS: EMPIRICAL CORRELATION FOUND IN BINARY OXIDES

1992 ◽  
Vol 06 (28) ◽  
pp. 1819-1825 ◽  
Author(s):  
M. RENTERÍA ◽  
C.P. MASSOLO ◽  
A.G. BIBILONI
Keyword(s):  
Electric Field ◽  
Electric Field Gradient ◽  
Field Gradient ◽  
Near Neighbor ◽  
Coupling Constants ◽  
Local Component ◽  
Binary Oxides ◽  
Field Gradients ◽  
Wide Range ◽  
Data Points

For the first time a well defined correlation between local and lattice contributions of the electric field gradient in semiconductors and insulators is presented. The local component of the electric field gradient in binary oxides, originated in extraionic contributions, is extracted from all quadrupole coupling constants measured in Perturbed Angular Correlation experiments with 111Cd probes. The resulting systematics reveals a linear dependence of the local component over a wide range of ionic efg values, both contributing with opposite signs. The clustering of the data points is explained in terms of the oxygen near neighbor symmetry.

Assignment and structural dependence of electric field gradients in anorthite and simple field gradient calculations in some aluminosilicates

1974 ◽  
Vol 140 (5-6) ◽  
Author(s):  
J. L. Staehli ◽  
D. Brinkmann
Keyword(s):  
Electric Field ◽  
Field Gradient ◽  
Quadrupole Coupling Constant ◽  
Coupling Constant ◽  
Electric Field Gradients ◽  
Point Charge Model ◽  
Polarization Effects ◽  
Field Gradients ◽  
Charge Model ◽  
Quadrupole Coupling

AbstractThe electric field gradient tensors at theIt was found that the quadrupole coupling constant is correlated with the distortion of the coordination tetrahedra and that the simple point-charge model which neglects polarization effects is apt to yield quite satisfying results for very distorted tetrahedra.Similar results were obtained for the Al and Na sites in albite, NaAlSi

The Nuclear Quadrupole Moment of 14N from Accurate Electric Field Gradient Calculations and Microwave Spectra of NP Molecule

2007 ◽  
Vol 72 (1) ◽  
pp. 64-82 ◽  
Author(s):  
Vladimir Kellö ◽  
Andrzej J. Sadlej
Keyword(s):  
Electric Field ◽  
Electric Field Gradient ◽  
Field Gradient ◽  
Quadrupole Moment ◽  
Quadrupole Coupling Constant ◽  
Basis Sets ◽  
Field Gradients ◽  
Nuclear Quadrupole Coupling Constant ◽  
Nuclear Quadrupole Moment ◽  
Nuclear Quadrupole

Extensive series of relativistic coupled cluster calculations of the electric field gradient at N in NP has been carried out. The accurate value of the calculated electric field gradient, combined with the highly accurate experimental value of the nuclear quadrupole coupling constant for the 14N nucleus, gives the 'molecular' value of the nuclear quadrupole moment Q(14N) = 20.46 mb. This result perfectly agrees with the value (20.44 ± 0.03 mb) determined from atomic calculations and atomic spectra. The present study involves also extensive investigations of basis sets which must be used in highly accurate calculations of electric field gradients.

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