[CP2K:2110] Re: Inconsistency in molecular dipole calculation

[Teodoro Laino]

Fawzi,
this:

> The molecular dipole on the other hand tries to calculate the dipole wrt. to the center of the molecule. Maybe in the definition of that it can jump (if the cell is smaller than 2 timese the molecule it can guess the "wrong" center.
>   
is not correct!
Molecular dipole can have whatever center you want (you can specify in 
the input) [that's part of my today's patch!] and the jump at cell/2 is 
not there anylonger (through the input you have full flexibility in 
choosing the reference point and whether you want it periodic or not.. 
just like the TOTAL_DIPOLE).
So if you have 1 molecule: the TOTAL_DIPOLE and MOLECULAR_DIPOLE will  
ALWAYS be identical if computed with the same reference point.

So.. again.. if the error is there.. is there for both.. but I'm ready 
to be denied.
Teo

> If you express the dipole in au. (or reduced unit) then the jump should be readily corrected.
> Better ways to define the reference point for the molecule are obviously welcome, or maybe you really found a bug, can you explain a little more?
>
> One thing that I saw for ionic thing the direct method (which in general is much faster) needs to be converged to *very* high accuracy to avoid jumps in the localization during an md.
>
> ciao
> Fawzi
> Teodoro Laino wrote:
>   
>> The way it is computed is similar to TOTAL_DIPOLE. This means that you 
>> should get big problems as well
>> with the TOTAL_DIPOLE..
>>
>> There could be a bug somewhere both in TOTAL_DIPOLE and 
>> MOLECULAR_DIPOLES for non-orthorombic cells..
>> Is this the case?
>>
>>
>> Daniele Passerone wrote:
>>     
>>> Dear Teodoro, is it possible that this postprocessing part does not
>>> work with non-orthorombic cells?
>>>
>>> We tried with our cell and got again big problems...
>>>
>>>
>>> daniele
>>>
>>>
>>>   
>>>       
>>     
>
>
>