How to specify the magnetic moment of each atom?

[stclair]

Hi, Matt,

Thanks great for your helpful reply. I will give a try with 
'CORE_CORRECTION.

For the broken symmetry, I have tried it by setting the initial guess of 
the Ce atom as Ce3+ (only for the Ce atoms I want to localize the 
electrons). I attached the 'KIND' section for these Ce atoms. But I got the 
following error message:
 *************************************************************************
 *** 15:35:59 ERRORL2 in qs_subsys_methods:num_ao_el_per_molecule ::   ***
 *** SECOND SPIN CONFIG IS IGNORED WHEN MOLECULAR STATES ARE ASSIGNED! ***
 *************************************************************************
I checked the source file from 
http://cp2k.web.psi.ch/doxygen/trunk/de/d42/qs__subsys__methods_8f90_source.html. 
It seems due to the different initial guess for Alpha and beta and only 
Alpha will be used for calculation. Is that correct?
Could you help check if there is anything wrong in my setting?

The basis set for Ce I am using is from a recent paper: JPCC, 2013, 117, 
23082.

Thanks great!

Best,
Lei



On Thursday, February 26, 2015 at 4:16:42 AM UTC-6, Matt W wrote:
>
> Hi,
>
> you can get what you are after by using the broken symmetry (&BS) keyword 
> within the &KIND block. It is a bit fiddly to use, but can be used to 
> specify the atomic guess used to generate the initial density matrix. The 
> are some threads in the forum and some stuff online if you look for it.
>
> But, my preferred way of _trying_ to localize the spins is to use the 
> &CORE_CORRECTION keyword, again in the &KIND section. So in this case pick 
> the two Ce that you want to localize the electrons onto and make them a new 
> kind in your geometry file (Ce3 or something). Then in &KIND Ce3 add 
> &CORE_CORRECTION 0.5 or 1.0.  This increases the effective nuclear charge 
> of these atoms and makes it very likely the electrons will localize on 
> them. You can then do a rough geometry relaxation to get the lattice 
> distortion that might stabilize the localized electrons. Then you can 
> restart but setting the &CORE_CORRECTION back to 0.0. If you are using an 
> appropriate density functional then you have a decent chance of getting the 
> localization you want. For the O vac in CeO2 you can just run a triplet 
> calculation with the modified core charge on a couple of Ce and you should 
> get what you want without bothering with the broken symmetry guess.
>
> Matt
>
> On Thursday, February 26, 2015 at 6:23:01 AM UTC, stclair wrote:
>>
>> Dear CP2K user,
>>
>>     I am working on CeO2 (111) surface with oxygen vacancy. Based on the 
>> previous studies, two extra electrons should locate on two next-nearest Ce 
>> atoms (as shown in the attached pictures). But my calculation converges to 
>> a different electronic configuration where the extra electrons locate on 
>> the Ce atoms closest to vacancy. Is there any keywords I can use to specify 
>> the magnetic moment for the atoms? Some keywords are similar to MAGMOM in 
>> VASP?
>>
>>    Thanks in advance.
>>
>> Best,
>> Lei
>>
>
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