[Wien] [Wien2k User Group] Volume optimization of Zirconium

[Peter Blaha]

optimizing c/a and optimizing the volume are two different things.

The fit with some eos should only be done for volume optimization, but of course
NOT for c/a optimizations. Maybe this is the reason for your "scatter" ???

When you read the UG, chapeter 5.3 you will find more information.

The analysis with an eos is only for VOLUME !!! and needs an input file case.analysis
with volume/e-tot.

For EACH volume you can do a c/a optimization and then put the best energy for this
volume into case.analysis .  In order to be able to do this, you need to "understand"
what you are doing.

Another possibility is to use   parabolfit_lapw  (see UG).

However, there is even an alternative listed in the UG (did you read it ?). It is called 2Doptimize
This is probably what you want to use in your case.

Ghosh SUDDHASATTWA schrieb:
> Dear Michael, 
> I guess the values of the energy volume and pressure comes in the same
> window as the energy curve. 
> I am not able to figure what you actually mean by saying that "optimize c/a
> ratio" and" equation of state from volume optimization. 
> The energy curve in fact comes from optimize.job and fitting parameters by
> fitting a suitable eos. 
> 
> Suddhasattwa 
> 
> -----Original Message-----
> From: wien-bounces at zeus.theochem.tuwien.ac.at
> [mailto:wien-bounces at zeus.theochem.tuwien.ac.at] On Behalf Of Michael
> Fischer
> Sent: Monday, January 11, 2010 1:57 PM
> To: wien at zeus.theochem.tuwien.ac.at
> Subject: [Wien] [Wien2k User Group] Volume optimization of Zirconium
> 
> I get more and more confused what you actually want to do. 
> 
> Do you want to optimize the c/a ratio or calculate the equation of state
> from a volume optimization?
> 
> If I understand the output you supplied correctly, you tried to obtain the
> bulk modulus from the optimization of the c/a ratio, which doesn't make
> sense.
> 
> Moreover, you must of course use more than just two points for the fit of
> the equation of states!
> 
> Have you familiarized yourself with the TiC example which is explained in
> the UG?
> 
> Best regards
> Michael

-- 

                                       P.Blaha
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Peter BLAHA, Inst.f. Materials Chemistry, TU Vienna, A-1060 Vienna
Phone: +43-1-58801-15671             FAX: +43-1-58801-15698
Email: blaha at theochem.tuwien.ac.at    WWW: http://info.tuwien.ac.at/theochem/
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