metal ions in cp2k

Qiang Li qiangl... at
Sun Nov 13 08:47:12 CET 2016

Dear Vladimir,

The UKS does not help to separate the charges, as I expected. I did a 
calculation with same system by Gausssian 09 for a test, and the Mulliken 
charge analysis shows that the Na(+1)Cl(-1) are well separated. I do expect 
similar result from CP2k, since it also describes the valence electrons 
with gaussian basis sets.  I am uploading the input file for my cp2k run, 
which you can have a quick look whether I did something wrong or not.

Thank you for being replying.

Best regards,

在 2016年11月10日星期四 UTC+8下午7:51:26,Vladimir Rybkin写道:
> Hi Li,
> this means you have a "covalent" dissociation into atoms, not ions. Try to 
> do a spin-unrestricted calculation, i.e. UKS (alternative name - LSD) 
> calculation in the DFT section.
> Yours,
> Vladimir
> четверг, 10 ноября 2016 г., 12:01:16 UTC+1 пользователь Qiang Li написал:
>> Hi, Vladimir,
>> Thanks for your reply, that was quite helpful.
>> I did some tests before I reply back. Simply, I calculated Na+Cl- system 
>> (distance is set to 10 angstrom, using a 20x10x10 box), and did the 
>> Mulliken charge analysis. I found that using  GPW method, i.e. using the 
>> GTH potential and DZVP basis set (same method in this paper: 
>>, the charges was 
>> Na(0.5)Cl(-0.5), which is very strange to me. Alternatively, the charges 
>> are well separated when I apply GAPW method (Na+Cl-).
>> What's the physics behind this?
>> Best regards,
>> Li
>> 在 2016年11月8日星期二 UTC+8下午11:03:55,Vladimir Rybkin写道:
>>> Dear Li,
>>> there are Mulliken and Hirshfeld population analyses in CP2K, which 
>>> provide partial charges on atoms. 
>>> To keep charges separated you need a large simulation cell. 
>>> Alternatively, you may consider a charged cell (no counter ions). This is 
>>> simpler to do, although, the large cell is even more a must.
>>> Yours,
>>> Vladimir 
>>> вторник, 8 ноября 2016 г., 15:31:07 UTC+1 пользователь Qiang Li написал:
>>>> Dear all,
>>>> I found several publications dealing with metal ions in the AIMD 
>>>> calculations, Zn(2+) for example. The way I see it is that the authors use 
>>>> Cl- counter ions to neutralize the system. However, how one can make 
>>>> sure that the charge of the two ions are well separated, i.e. Zn (2+) and 
>>>> Cl (-1) ? is there any charge analysis available  in CP2K 4.1 ? Any 
>>>> suggestions are appreciated.
>>>> All the bests,
>>>> Li
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