FIXED_MAGNETIC_MOMENT can't work

[Qiang Yue]

Dear CP2K forum,

I did structure optimization simulations with restricted total magnetization.

There were 129 carbon atoms in my system with 0.3 μ_B/atom.

So I set MULTIPLICITY as 40, and FIXED_MAGNETIC_MOMENT as 39.

But the simulation stopped with error like this:

So I turned off the keyword MULTIPLICITY, which will be set as 1 automatically.

This time my calculation could work. But there were strange things in the output file:

As shown in two figure above, there are same numbers of up electrons and down electrons at every iteration, and the iteration converges. But after the iteration over, Mulliken population analysis shows there are difference in the number of  up electrons and down electrons as my prediction. 

My question is whether the parameters (MULTIPLICITY=1 and FIXED_MAGNETIC_MOMENT =39 ) are right for my calculation? 

If not, could you please give me some suggestions ? Thank you.

Sincerely yours,

Yue Qiang

[Krack Matthias]

Hi Yue

 

MULTIPLICITY is an optional keyword that defines only the initial multiplicity of the system, i.e. the initial number (distribution) of spin-up and spin-down electrons. That is, however, overwritten by the constraint FIXED_MAGNETIC_MOMENT during a run with SMEARing active. Note, that the multiplicity is no longer a well-defined quantity with SMEARing.

 

HTH

 

Matthias

 

From: cp...@googlegroups.com <cp...@googlegroups.com> on behalf of Qiang Yue <yue...@gmail.com>
Date: Thursday, 2 November 2023 at 02:48
To: cp2k <cp...@googlegroups.com>
Subject: [CP2K:19449] FIXED_MAGNETIC_MOMENT can't work

Dear CP2K forum,

 

I did structure optimization simulations with restricted total magnetization.

There were 129 carbon atoms in my system with 0.3 μ_B/atom.

So I set MULTIPLICITY as 40, and FIXED_MAGNETIC_MOMENT as 39.

But the simulation stopped with error like this:

 

 

So I turned off the keyword MULTIPLICITY, which will be set as 1 automatically.

This time my calculation could work. But there were strange things in the output file:

 

As shown in two figure above, there are same numbers of up electrons and down electrons at every iteration, and the iteration converges. But after the iteration over, Mulliken population analysis shows there are difference in the number of  up electrons and down electrons as my prediction. 

 

My question is whether the parameters (MULTIPLICITY=1 and FIXED_MAGNETIC_MOMENT =39 ) are right for my calculation? 

If not, could you please give me some suggestions ? Thank you.

 

Sincerely yours,

Yue Qiang

--
You received this message because you are subscribed to the Google Groups "cp2k" group.
To unsubscribe from this group and stop receiving emails from it, send an email to cp2k+uns...@googlegroups.com.
To view this discussion on the web visit https://groups.google.com/d/msgid/cp2k/710ec7f4-b101-4f31-abbf-102de4785564n%40googlegroups.com.