scholarly journals Towards an ab initio theory for the temperature dependence of electric field gradients in solids: Application to hexagonal lattices of Zn and Cd

2020 ◽  
Vol 101 (6) ◽  
Author(s):  
A. V. Nikolaev ◽  
N. M. Chtchelkatchev ◽  
D. A. Salamatin ◽  
A. V. Tsvyashchenko
Keyword(s):  
Electric Field ◽  
Ab Initio ◽  
Temperature Dependence ◽  
Electric Field Gradients ◽  
Field Gradients ◽  
Ab Initio Theory

Experimental and ab initio study of the electric field gradients at Ta and Cd impurities in TiAl3

2009 ◽  
Vol 479 (1-2) ◽  
pp. 56-59 ◽  
Author(s):  
P. Wodniecki ◽  
A. Kulińska ◽  
B. Wodniecka ◽  
J. Belošević-Čavor ◽  
V. Koteski
Keyword(s):  
Electric Field ◽  
Ab Initio ◽  
Ab Initio Study ◽  
Electric Field Gradients ◽  
Field Gradients

Molecular electric moments and electric field gradients from X-ray diffraction data: model studies

1996 ◽  
Vol 52 (6) ◽  
pp. 1023-1035 ◽  
Author(s):  
M. A. Spackman ◽  
P. G. Byrom
Keyword(s):  
Electric Field ◽  
Ab Initio ◽  
Diffraction Data ◽  
Moment Tensor ◽  
General Pattern ◽  
Valuable Insight ◽  
X Ray Diffraction ◽  
Electric Field Gradients ◽  
X Ray ◽  
Field Gradients

Model X-ray data sets, with and without the inclusion of experimental thermal motion parameters, have been computed via Fourier transformation of ab initio molecular electron densities for 12 different molecular crystals. These datasets were then analysed with three different multipole models of varying sophistication and, from the multipole functions, molecular dipole and second moments, as well as electric field gradients (EFG's), at each nuclear site were computed and compared with results obtained from the original ab initio wavefunctions. The results provide valuable insight into the reliability of these properties, extracted in the same way from experimental X-ray data. Not all molecular systems display identical trends, but a general pattern is discernible. Specifically, dipole moments are typically underestimated by a small but significant amount (~ 10–15%), the trace of the second moment tensor is well determined but overestimated by a few per cent and electric field gradients at protons are confirmed to be well within reach of a careful charge density analysis of X-ray diffraction data.

scholarly journals Electric field gradients in MgB2 synthesized at high pressure: 111Cd TDPAC study and ab initio calculation

2001 ◽  
Vol 119 (3) ◽  
pp. 153-158 ◽  
Author(s):  
A.V. Tsvyashchenko ◽  
L.N. Fomicheva ◽  
M.V. Magnitskaya ◽  
E.N. Shirani ◽  
V.B. Brudanin ◽  
...  
Keyword(s):  
High Pressure ◽  
Electric Field ◽  
Ab Initio ◽  
Ab Initio Calculation ◽  
Electric Field Gradients ◽  
Field Gradients ◽  
Tdpac Study

Ab initio studies of electric field gradients and magnetic properties of uranium dipnicties

RSC Advances ◽  
2015 ◽  
Vol 5 (47) ◽  
pp. 37592-37602 ◽  
Author(s):  
E. Ghasemikhah ◽  
S. Jalali Asadabadi ◽  
Iftikhar Ahmad ◽  
M. Yazdani-Kacoei
Keyword(s):  
Magnetic Properties ◽  
Electric Field ◽  
Ab Initio ◽  
Orbit Coupling ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Electric Field Gradients ◽  
Field Gradients

In this paper, we explore the electric field gradients (EFGs) at 238U sites for antiferromagnetic UX2 (X = P, As, Sb, Bi) dipnicties using LDA, LDA + U, GGA, GGA + U, and EECE schemes in the presence of spin–orbit coupling.

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.

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