[CP2K-user] [CP2K:13603] Magnetic Fe

[Krack Matthias (PSI)]

Hi Andrew

Set the keyword MULTIPLICITY<https://manual.cp2k.org/cp2k-6_1-branch/CP2K_INPUT/FORCE_EVAL/DFT.html#MULTIPLICITY> to the appropriate value, i.e. the desired difference between alpha and beta electrons plus one. Moreover, you can specify the initial electronic configuration for each atomic kind using the BS section<https://manual.cp2k.org/cp2k-6_1-branch/CP2K_INPUT/FORCE_EVAL/SUBSYS/KIND/BS.html>.

HTH

Matthias

From: cp... at googlegroups.com <cp... at googlegroups.com> On Behalf Of Andrew Horsfield
Sent: Montag, 6. Juli 2020 16:01
To: cp2k <cp... at googlegroups.com>
Subject: [CP2K:13603] Magnetic Fe

I am attempting to carry out a calculation for ferromagnetic bcc Fe using CP2K 6.1. Attached are the input and output files.

The calculation runs to completion, but I am confused by the output. The multiplicity is not 1

 Orbital energies  State     Spin  L     Occupation   Energy[a.u.]    Energy[eV]

                       1    alpha  0          1.000      -3.533760    -96.158487
                       2    alpha  0          1.000      -0.171394     -4.663878
                       1     beta  0          1.000      -3.422092    -93.119858
                       2     beta  0          1.000      -0.151638     -4.126285

                       1    alpha  1          3.000      -2.201116    -59.895424
                       1     beta  1          3.000      -2.092954    -56.952177

                       1    alpha  2          4.250      -0.282066     -7.675405
                       1     beta  2          1.750      -0.191730     -5.217225
yet the system appears to have zero spin moment:

 !-----------------------------------------------------------------------------!
                     Mulliken Population Analysis

 #  Atom  Element  Kind  Atomic population (alpha,beta) Net charge  Spin moment
       1     Fe       1         8.000000     8.000000     0.000000     0.000000
       2     Fe       1         8.000000     8.000000     0.000000    -0.000000
 # Total charge and spin       16.000000    16.000000     0.000000    -0.000000

 !-----------------------------------------------------------------------------!

Between these blocks of output seems to be a rescaling step which might explain the discrepancy:

Spin 1
 Re-scaling the density matrix to get the right number of electrons for spin 1
                  # Electrons              Trace(P)               Scaling factor
                           16                18.500                        0.865

 Spin 2
 Re-scaling the density matrix to get the right number of electrons for spin 2
                  # Electrons              Trace(P)               Scaling factor
                           16                13.500                        1.185
Can anyone explain what is happening here and how I allow the system to be magnetic? Is there a keyword I need to add?

--
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 cp... at googlegroups.com<mailto:cp... at googlegroups.com>.
To view this discussion on the web visit https://groups.google.com/d/msgid/cp2k/75d21ca6-b2cf-4273-9f34-35f58986c743o%40googlegroups.com<https://groups.google.com/d/msgid/cp2k/75d21ca6-b2cf-4273-9f34-35f58986c743o%40googlegroups.com?utm_medium=email&utm_source=footer>.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.cp2k.org/archives/cp2k-user/attachments/20200707/77eabaaa/attachment.htm>