[Wien] Large difference in calculated and experimental EFG

[Stefaan Cottenier]

If the goal is to have a EFG that is a predictive as possible for experiment, then it is advised to take the experimental cell parameters (but with position optimization).

If that EFG does not agree with experiment, then this is a trigger to search further. There can be many reasons (assuming both the experiment and the calculation are correctly done):


  *   You have an unusually sensitive case, where small details that usually do not matter do affect the EFG
  *   The effect of temperature might be unusually large (your calculation is at 0 K)
  *   Maybe the Ta atom is associated with a defect (vacancy, oxygen,…) and the experiment measures that complex.
  *   …

Stefaan



From: Wien <wien-bounces at zeus.theochem.tuwien.ac.at> On Behalf Of Ramsewak Kashyap
Sent: Monday, March 18, 2019 12:41 PM
To: A Mailing list for WIEN2k users <wien at zeus.theochem.tuwien.ac.at>
Subject: Re: [Wien] Large difference in calculated and experimental EFG

atomic positions  optimization means force relaxation.. I have did that. but I am asking about cell parameter optimization. Is it necessary for .cif file getting form COD??
Thanks


On Mon, Mar 18, 2019 at 4:55 PM Stefaan Cottenier <Stefaan.Cottenier at ugent.be<mailto:Stefaan.Cottenier at ugent.be>> wrote:
Yes, optimization of the atomic positions is absolutely necessary to have a meaningful value for Vzz and eta in a supercell.

Stefaan


From: Wien <wien-bounces at zeus.theochem.tuwien.ac.at<mailto:wien-bounces at zeus.theochem.tuwien.ac.at>> On Behalf Of Ramsewak Kashyap
Sent: Monday, March 18, 2019 12:23 PM
To: A Mailing list for WIEN2k users <wien at zeus.theochem.tuwien.ac.at<mailto:wien at zeus.theochem.tuwien.ac.at>>
Subject: [Wien] Large difference in calculated and experimental EFG

Hi Wien2k users,
I am doing EFG calculation for TiNi monoclinic phase, but I am getting large difference in Calculated and measured value, I have taken parameters from COD, then make 2x2x2 supercell and replace one Ti with Ta atom... is structural optimization is necessary??  and eta value was also quite large as compare to measured value.

--
Ramsewak Kashyap
Saha Institute of Nuclear Physics
9473811023
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--
Ramsewak Kashyap
Saha Institute of Nuclear Physics
9473811023
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