[CP2K:2886] Re: Problems of IR and dipole calculation

[Mathieu Salanne]

Hi Ross,

Before looking at the IR spectrum you may now look at the dipoles trajectory, taking into account the 1/V factor between CPMD and CP2K. Do the dipoles look the same? Then, if not, does the Wannier centers location change a lot?

Mathieu

Le 20 oct. 2010 à 13:38, Fawzi Mohamed a écrit :

> 
> On 20-ott-10, at 12:20, Ross, Sun wrote:
> 
>> Hi Mathieu,
>> Thanks for replying.
>> I used the fourier code in CPMD and dipoles calculated with cp2K
>> (format was modified) to calculated IR spectrum. And I find that the
>> peaks are too noisy and the positions some main peaks are not
>> accurate. (Simulated time >10ps and >600 data points in IR spectrum).
>> Any advise?
> 
> cp2k peaks are more noisy?
> The way you do it you always localize all wannier centers. If that fails, or is done with a large error then you might have "jumps" in the trajectory.
> Any kind of jumps will add to the noise of the FFT.
> 
> Fawzi
>> 
>> Regards,
>> Ross, SUN
>> 
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