[Wien] Finding the preferred site

[Peter Blaha]

Of course you have to use mini-positions first.

An if you want to optimize the voluem, you have to redo mini for each 
volume.

On 02/06/2013 09:28 AM, Seyyed Mojtaba Zareii (Alavi Sadr) wrote:
> Hi dear wien2k users
> I want to investigate the effect of Hydrogen absorption in
> LaNi4.5Sn0.5 compound as H atom will occupy the interstitial site to
> form LaNi4.5Sn0.5H hydride. I could simulate parent compound,
> LaNi4.5Sn0.5, successfully, but I have a problem with finding the
> preferred occupied site for H atom:
> It seems that there are two approaches to find the preferred site for
> H to be occupied as follows:
> 1-	One can find the preferred site occupation with evaluating the
> total energy of the system for different positions of the H site and
> finding more negative energy via optimization program (energy versus
> volume).
>          In this way, we don’t use the mini-position program (force
> minimization for H atom).
> OR
> 2-	Putting H atom in the possible different sites, first one should do
> mini-position program to find the relaxed location for H atom where
> Hellmann-Feynman forces were minimized. After obtaining the relaxed
> Hydrogen position for each model, do the optimization program (Energy
> versus Volume) for the same structures to find the structure with more
> negative energy as preferred site for H.
> Which approach is correct? Is there any approach for this problem?
>
> Thank you
> Zareii
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>

-- 

                                       P.Blaha
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Peter BLAHA, Inst.f. Materials Chemistry, TU Vienna, A-1060 Vienna
Phone: +43-1-58801-165300             FAX: +43-1-58801-165982
Email: blaha at theochem.tuwien.ac.at    WWW: 
http://info.tuwien.ac.at/theochem/
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