[CP2K:2890] Re: Problems of IR and dipole calculation

Fawzi Mohamed fa... at gmx.ch
Tue Nov 2 11:10:42 UTC 2010

On 28-ott-10, at 02:36, Ross, Sun wrote:

> Hi Mathieu and Fawzi,
Hi Sun Ross,

> I tested the dipoles again and again. The problem still happened
> (dipole jumps and bad wannier center), then I took Mr. Teodoro Laino's
> advise to set the inputfile as follows, and it works. The wannier
> centers are at reasonable position and the values of dipoles seem
> right. But I still get a question, as CPMD mannual goes "TUCKERMAN
> Method: - box size : molecule + 3 Ang. border AND 2*size of charge
> distribution". If center molecule at 0. 0. 0., that means "molecule +
> 3 Ang. border" fails, right? And it still puzzles me that why setting
> "CENTER_POINT 0. 0. 0." could give the right result. Any advise?

> 1) CENTER your system in 0. 0. 0.
>             CENTER_POINT 0. 0. 0.
>        &END
>    &END
> 2) Use MT (which is translational invariant) instead of WAVELET (which
> forces the system to be between 0 and L) as POISSON_SOLVER.

No Tuckerman method is translational invariant, the only important  
thing is that the charge density must be smaller than half the box size.
As the charge density is larger than just the position of the cores  
you should put 2*(box containting the cores+some slack for the  
density( ~3Å)



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