[CP2K-user] DFT+U calculations for Cr3+ in MgCl2-KCl melts

[Vyacheslav Bryantsev]

Dear CP2K Group,

There are a couple of ways to setup antiferromagnetic calculations for 6 
Cr3+ ions (3d3 state) dissolved in MgCl2-KCl melt. 

One way is to use MAGNETIZATION keyword. Another way is to use the BS 
section (commented below)

&KIND Cr1
      ELEMENT Cr
      BASIS_SET DZVP-MOLOPT-SR-GTH
      POTENTIAL GTH-PBE-q14
      *MAGNETIZATION 4.0*
      &DFT_PLUS_U
        L 2
        U_MINUS_J 0.1234777
        # U = 3.36 eV
        U_RAMPING 0.01234777
       &END DFT_PLUS_U
 









*!       &BS !        &ALPHA !         NEL +1 -1 !         L 2 0 !         
N 3 4 !       &END ALPHA !       &BETA !        NEL -5 -1 !        L 2 0 ! 
       N 3 4 !      &END BETA*
     &END BS
    &END KIND
    &KIND Cr2
      ELEMENT Cr
      BASIS_SET DZVP-MOLOPT-SR-GTH
      POTENTIAL GTH-PBE-q14
      *MAGNETIZATION -4.0*
      &DFT_PLUS_U
        L 2
        U_MINUS_J 0.1234777
        # U = 3.36 eV
        U_RAMPING 0.01234777
       &END DFT_PLUS_U










*!       &BS!        &ALPHA!         NEL -5 -1!         L 2 0!         N 3 
4!       &END ALPHA!       &BETA!        NEL +1 -1!        L 2 0!        N 
3 4!      &END BETA*
    &END KIND

The problem I have is that the total E from two setups (MAGNETIZATION and 
BS) can be somewhat different:
For example, the Etot of a system (mol fractions are shown) is lower when 
setting up calculations using BS
50-MgCl2-50-KCl-5-CrCl3
Etot = -8997.64290729994173 using BS section
Etot = -8997.62650294793639 using MAGNETIZATION keyword

However, for a different composition, the Etot is lower using MAGNETIZATION 
15-MgCl2-85-KCl-5-CrCl3
Etot = -6895.30145964661006 using BS section
Etot = -6895.31001188029859 using MAGNETIZATION keyword

The resulting spin moment on each Cr3+ in both cases are close to +3 and 
-3, as expected.


*What are the general recommendations to correctly find a ground electronic 
state using DFT+U for transition metal ions in solution/melts?*

*Are there any additional checks one can do to make sure the ground 
electronic state is found?*
After the ground electronic state is found, the next step will be to run 
AIMD simulations. 
The input and output files for these examples are given as attachments.

Thank you,
Slava




-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.cp2k.org/archives/cp2k-user/attachments/20190424/eb502722/attachment.htm>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: 50-50-5-magnetization.inp
Type: chemical/x-gamess-input
Size: 3908 bytes
Desc: not available
URL: <https://lists.cp2k.org/archives/cp2k-user/attachments/20190424/eb502722/attachment.inp>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: 50-50-5-magnetization.out
Type: application/octet-stream
Size: 256067 bytes
Desc: not available
URL: <https://lists.cp2k.org/archives/cp2k-user/attachments/20190424/eb502722/attachment.obj>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: 50-50-5-bs.inp
Type: chemical/x-gamess-input
Size: 4785 bytes
Desc: not available
URL: <https://lists.cp2k.org/archives/cp2k-user/attachments/20190424/eb502722/attachment-0001.inp>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: 50-50-5-bs.out
Type: application/octet-stream
Size: 262637 bytes
Desc: not available
URL: <https://lists.cp2k.org/archives/cp2k-user/attachments/20190424/eb502722/attachment-0001.obj>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: 15-85-5-magnetization.inp
Type: chemical/x-gamess-input
Size: 3908 bytes
Desc: not available
URL: <https://lists.cp2k.org/archives/cp2k-user/attachments/20190424/eb502722/attachment-0002.inp>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: 15-85-5-magnetization.out
Type: application/octet-stream
Size: 285617 bytes
Desc: not available
URL: <https://lists.cp2k.org/archives/cp2k-user/attachments/20190424/eb502722/attachment-0002.obj>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: 15-85-5-bs.inp
Type: chemical/x-gamess-input
Size: 4787 bytes
Desc: not available
URL: <https://lists.cp2k.org/archives/cp2k-user/attachments/20190424/eb502722/attachment-0003.inp>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: 15-85-5-bs.out
Type: application/octet-stream
Size: 265786 bytes
Desc: not available
URL: <https://lists.cp2k.org/archives/cp2k-user/attachments/20190424/eb502722/attachment-0003.obj>