[CP2K-user] computation does not yet treat fractional occupied orbitals

[Marcella Iannuzzi]

Dear Wang,

yes, you should use smearing. 
The multiplicity is a global property and it is not assigned per atom or 
per kind. 
Anyway, I would first converge the electronic structure without imposing 
constraints. 
In principle the resulting electronic distribution should correspond to the 
DFT minimum energy. 
Kind regards
Marcella
 

On Tuesday, September 15, 2020 at 6:09:18 PM UTC+2 ma... at gmail.com wrote:

> Dear Marcella,
>
>  
>
> Thanks for your reply. I am studying the adsorption of nitrogen molecule 
> on Ru surface.
>
>  So, under these circumstances should I add SMEAR or not? And if I should, 
> how can I setting FIXED_MAGNETIC_MOMENT in the case of Involving two 
> different kinds of atoms?
>
>  
>
> Best Regards,
>
> Wang
>
> 在2020年9月15日星期二 UTC+8 下午7:07:26<Marcella Iannuzzi> 写道：
>
>> Dear Wang
>>
>> you can fix the number of electrons per spin channel when using smearing 
>> by activating the keyword
>> FIXED_MAGNETIC_MOMENT 
>> <https://manual.cp2k.org/cp2k-7_1-branch/CP2K_INPUT/FORCE_EVAL/DFT/SCF/SMEAR.html#FIXED_MAGNETIC_MOMENT>
>> in the section SMEAR. 
>> Whether for metallic systems this physically makes sense is to be 
>> demonstrated. 
>> The states around the Fermi energy of metallic systems would anyway show 
>> fractional occupation, which prevents the S**2 computation
>> If your system is not metallic, do not use SMAER. 
>> Kind regards,
>> Marcella
>> On Tuesday, September 15, 2020 at 9:57:56 AM UTC+2 ma... at gmail.com 
>> wrote:
>>
>>> Hi, 
>>>
>>>
>>> I want to ask whether MUTIPLICITY can be used with SMEAR? When I use 
>>> them together, the WARNING appears as ‘WARNING: S**2 computation does not 
>>> yet treat fractional occupied orbitals’. Can anyone give me some 
>>> suggestions to deal with it. And here are my input file and out file. 
>>>
>>>
>>> Thanks very much.
>>>
>>>
>>> Best Regards,
>>> Wang
>>>
>>
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