[gpaw-users] wannier functions

[Jens Jørgen Mortensen]

On 14-02-2012 11:29, Sampsa Riikonen wrote:
> 02.02.2012 22:24, Kristian Sommer Thygesen kirjoitti:
>> Dear Sampsa
>>
>> It should be fine. Make sure you only use the occupied states when you construct the WFs. Also note that the algorithm can be trapped in local minima. This problem is reduced if you make a reasonable initial guess e.g. atomic orbitals (i cannot remember if this is default)
> The wannier function class can be seen here..
>
> https://wiki.fysik.dtu.dk/gpaw/epydoc/gpaw.wannier-pysrc.html
>
> method "gpaw.Wannier.wannier.localize" creates the wannier functions,
> but this method
> calls a function called "localize" which comes from..
>
> "from  _gpaw  import  localize"
>
> i.e. from the core functions written in C.
>
> So it becomes a bit difficult to see if atomic orbitals are used as an
> initial guess..
>
> How can this be controlled from the python level?

This algorithm doesn't use atomic orbitals.  It uses occupied states 
only and is quite robust - I would trust it.

Jens Jørgen

> Then there is another class called "gpaw.Wannier.wannier.LocFun"
> (inherited from "gpaw.Wannier.wannier")
> which seems to do something with the single-zeta (SZ) basis.
>
> What is this class and what is its difference with the original wannier
> class?
> Is it simply the projection of wavefunctions to the SZ basis?
>
> Regards,
>
> Sampsa
>
>> Best regards
>> Kristian
>> ________________________________________
>> From: gpaw-users-bounces at listserv.fysik.dtu.dk [gpaw-users-bounces at listserv.fysik.dtu.dk] On Behalf Of Sampsa Riikonen [sampsa.riikonen at iki.fi]
>> Sent: Thursday, February 02, 2012 7:22 PM
>> To: gpaw-users at listserv.fysik.dtu.dk
>> Subject: [gpaw-users] wannier functions
>>
>> Dear List,
>>
>> Is the wannier function implementation in gpaw reliable..?
>>
>> I am trying to calculate dipole moments of individual water molecules
>> in clusters as described in
>>
>> http://dx.doi.org/10.1103/PhysRevLett.82.3308
>>
>> i.e. using the wannier function centers, but I get exaggerated dipole
>> moment values (up to 20 %).
>>
>> Any thought on the subject would be apreciated..
>>
>> Regards,
>>
>> Sampsa
>>
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