Determination of Gradient-Elastic Constants in Cubic Solids

1972 ◽  
Vol 27 (8-9) ◽  
pp. 1235-1239 ◽  
Author(s):  
H. J. Hackeloer ◽  
O. Kanert
Keyword(s):  
Electric Field ◽  
Electric Field Gradient ◽  
Field Gradient ◽  
Point Defects ◽  
Elastic Constants ◽  
Lattice Distortion ◽  
Elastic Stress ◽  
Order Of Magnitude ◽  
The Given

Abstract The effect of static elastic stress on the NMR signal in LiCl35 , Rb85Cl35 , and Rb87Br is used to determine the gradient elastic constants relating the electric field gradient at the given nucleus to the elastic deformation. In contrast to previous experiments the quadrupole distortion produced by internal lattice distortion (point defects, dislocations etc.) is considered. Neglecting these distortions leads to an error in the determination of the gradient elastic constants by an order of magnitude.

Determination of electric field gradient parameters in tellurium

1976 ◽  
Vol 54 (16) ◽  
pp. 1692-1698 ◽  
Author(s):  
K. Hamilton ◽  
B. M. Powell ◽  
P. Martel
Keyword(s):  
Electric Field ◽  
Electric Field Gradient ◽  
Field Gradient ◽  
Inelastic Neutron Scattering ◽  
Mean Square Displacement ◽  
Inelastic Neutron ◽  
Charge Model ◽  
Bond Charge ◽  
Bond Charge Model

The relative intensities of the Mössbauer doublet in Te have been analysed at 4 K and 80 K by utilizing values of the mean square displacement tensor derived from inelastic neutron scattering measurements. The orientation β of the electric field gradient ellipsoid and its asymmetry parameter η have been determined. At 4 K, β = 90°, η = −0.17 and at 80 K, β = 92°, η = −0.48. A simple 'bond charge' model is proposed in an attempt to understand the discrepancy between these values of the electric field gradient parameters and those obtained theoretically by other authors.

Deuterium quadrupole splittings and hydrocarbon chain ordering in model membranes

1978 ◽  
Vol 56 (6) ◽  
pp. 678-680 ◽  
Author(s):  
Ronald Y. Dong
Keyword(s):  
Electric Field ◽  
Electric Field Gradient ◽  
Field Gradient ◽  
Axial Symmetry ◽  
Order Parameter ◽  
Hydrocarbon Chain ◽  
Correct Determination ◽  
Degree Of Orientation ◽  
Chain Ordering

It is pointed out that asymmetry in the electric field gradient is required for a correct determination of the order parameter tensor. Expressions for the quadrupole splittings of deuteriomethylene and deuteriomethyl groups are given without assuming axial symmetry in the electric field gradient and in the degree of orientation.

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