Low Spin (LS) and High Spin (HS) calculations ( from wien mailing list)

[Wien] Ls - HS

bothina hamad Thu, 26 Jun 2008 09:48:26 -0700 (PDT)

Daer Wien users,
                I'm trying to calculate the possible low-spin and high-spin 
states of La0.75Sr0.25CoO3 compound. In order to define the Low spin , I 
modified the case.inst file so the up and down spin of Co d-orbitals are equal, 
also for the case of high spin I put the maximum number of unpaired electrons.
See the files below:
Low spin
----------
Co
Ar 3  
3, 2,2.0  N
3, 2,2.0  N
3,-3,1.5  N
3,-3,1.5  N
4,-1,1.0  N
4,-1,1.0  N

High Spin
----------------
Co
Ar 3  
3, 2,2.0  N
3, 2,2.0  N
3,-3,3.0  N
3,-3,0.0  N
4,-1,1.0  N
4,-1,1.0  N



But In both cases I got a moment of 3.14 mb on the Co atom.

So what do you think is wrong, here?

Thanks in advance
Bothina

Stefaan Cottenier Thu, 26 Jun 2008 21:48:02 +0200

 

Search the usersguide for runfsm_lapw (fixed spin moment). Another way to stabilize different spin configurations is to use LDA+U with different density matrices as input and use -orbc for the first few iterations -- see the usersguide for -orbc.

Stefaan

Peter Blaha Fri, 27 Jun 2008 07:41:33 +0200

 

Use runsp_c_lapw to obtain the non-magnetic solution (or runfsm -m xxx when you want a low-moment FM state).Defining just different starting configuration may or may not lead to a desired self-consistent solution. This depends on the particular system and the way the scf-cycle proceeds.

  Reference: https://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/msg00656.html