[Wien] large deviation of atomic volume in BiNi compound

[pieper]

Dear Tomas,

at the moment I do not see something being obviously suspicious. Maybe 
the culprit is some structural phase transition invalidating the 
experimental structure you compare with. You might get one or two ideas 
from Stefaan Cottenier's work?

Error Estimates for Solid-State Density-Functional
Theory Predictions: An Overview by Means of the
Ground-State Elemental Crystals
K. Lejaeghere , V. Van Speybroeck , G. Van Oost & S. Cottenier

http://dx.doi.org/10.1080/10408436.2013.772503

Best regards,

Martin


---
Dr. Martin Pieper
Karl-Franzens University
Institute of Physics
Universitätsplatz 5
A-8010 Graz
Austria
Tel.: +43-(0)316-380-8564


Am 10.11.2015 13:05, schrieb Tomas Kana:
> Dear Martin and Gerhard,
> 
> Thank you for your suggestions. Gerhard, thank you for mentioning this
> 
> 
> experimental work. Will you please send me the pdf
> 
> of the article? I do not have access to it.
> 
> Regarding Martin's questions:
> 
> I tried to include magnetism
> 
> of the constituents by performing spin polarized calculations, too,
> 
> but the equilbrium volume was the same. The forces within the
> hexagonal unit cell
> 
> were not given in case.scf (I think there was too much symmetry
> operations).
> 
> However, I recently tried to express the hexagonal unit cell in a
> orthorhombic base
> 
> and cancel the symmetry operations by using inequivalent atoms
> 
> (I send the structure file in attachment). The volume was still wrong
> but
> 
> I know the values of the forces. For the experimental
> 
> atomic volume they were at most 0.84 mRy/a.u.
> 
> With best regards
> 
> Tomas Kana
> 
>> Since you ask for ideas and without really looking at the problem:
>> Assuming that the experimental numbers are correct, is this a room
>> temperature structure? The calculations are, of course, ground state
>> 
>> zero Kelvin, so things might go south if there is a phase transition
>> 
>> somewhere. Considering the elements you deal with maybe magnetic?
>> What
>> are the forces in your calculations?
>> 
>> Good luck,
>> 
>> Martin
> 
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