[Wien] EFG: theory Vs experiment for a case

[Ashwani Kumar]

hi,
   thanks for reply. the assymetry parameter, (Vxx-Vyy)/Vzz,  is zero
(wien2k calculation) whereas i got 0.52 from TDPAC (Time dependent
perturbed angular correlation) spectroscopy for a SrTiO3 (STO) defect
structure. EFG component is -1.63 x10^21 V/m2 (wien2k, lapw2 -efg) and i
obtained 1.69 x 10^21 V/m2 (calculated from TDPAC results). STO has cubic
lattice so no efg and no assymetry  parameter (for both wien2k and TDPAC)
but defect STO structure showed very pure hyperfine interactions with
assymetry parameter : 0.52. So i am not having confidence over my wien2k
calculation because :
1. i am getting assymetry parameter =0
2. Negative EFG which i understood from previous answers that negative sign
indicates the rate of decrease of z-component of EF wrt to distance.

Am i missing something?,
Calculation parameters are :Supercell (3x2x2) STO with doped Hf atom, PBE,
KGEN:200, rkmax: 7.0,

thanks,
A. Kumar

On Fri, Dec 14, 2018 at 11:02 PM Ashwani Kumar <ashwani.ism at gmail.com>
wrote:

> Hi,
>   i have calculated EFG  the defect structure of crystalline system from
> experimental data from PAC spectroscopy. Then using WIEN2K (crystal
> structure--> supercell--> defect introduced), EFG is calculated.
> Exper. Calculated : 1.69 x 10^21 V/m2 whereas wien2k calculation: -1.66 x
> 10^21 V/m2 (crude value still have to do lapw2 -efg) on probe atom. Wien2k
> calculation shows negative value. is there any significance of the negative
> sign.
>
> thanks,
> A. Kumar
>
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