a) I don't think that you will ever get a 3d-occupation which is in agreement with the "formal" valence (therfore this is called "formal"). This starts even for a very ionic TiO2, where formally the 3d electrons of Ti4+ should all be empty, but are not in reality.

b) Try to stabilize a "high-spin" state for Co by changing the 0.8 on spin-dn to 0.2, and the 0.59 to 0.9 in spin-up.
After modification of the dmatup/dn files, run:

x orb -up/dn
runsp -orbc
save constraint_high_spin
runsp -orb

and check the final results, if the spin (charge) state has changed.
Also compare the total energies of the present and the new solution.


On 05/10/2016 01:54 PM, Komal Bapna wrote:
Dear Prof. Peter
Thank you for your kind reply..

The Density matrix for Co up spin is..
          0.84607  0.00000  0.00000  0.00000 -0.08661
          0.00000  0.92206  0.00000  0.00000  0.00000
          0.00000  0.00000  0.59673  0.00000  0.00000
          0.00000  0.00000  0.00000  0.92206  0.00000
         -0.08661  0.00000  0.00000  0.00000  0.84607
Total electrons: 4.13298
and Density matrix for Co dn spin is:
          0.20583  0.00000  0.00000  0.00000  0.06263
          0.00000  0.80064  0.00000  0.00000  0.00000
          0.00000  0.00000  0.25923  0.00000  0.00000
          0.00000  0.00000  0.00000  0.80064  0.00000
          0.06263  0.00000  0.00000  0.00000  0.20583
Total electrons: 2.27217

This gives me the net spin moment of 1.86 muB on Co.
I understood by changing the occupancies we can change the spin state.
Still I am confused whether I can use these occupation numbers of
electrons in the respective orbitals to find the spin state of Co.Here,
total number of electrons is 6.4, 1.4 electrons higher than the expected
value for Co4+ ion. I may consider the extra electrons due to the
bonding of Co-O bonds. But, I am really unable to calculate the spin
state from the present configuration. Please suggest how to calculate
spin state for the given configuration, so that I can modify further.

Thanks and Regards

On Mon, May 9, 2016 at 3:59 PM, Komal Bapna <komal.ba...@gmail.com
<mailto:komal.ba...@gmail.com>> wrote:

    Sir,

    Its true that we can not generate "ionic" electron density with 
lstart/dstart. When I tried to modify .inst file according to the Co4+ ionic state, it 
showed error.

    My query is that how can we generate spin state configuration for such an 
ionic state, it spin states for Co and Co4+ are different and accordingly the 
magnetic moments.


    Please suggest.


    Thanks


    On Fri, May 6, 2016 at 3:18 PM, Komal Bapna <komal.ba...@gmail.com
    <mailto:komal.ba...@gmail.com>> wrote:

        Dear Wien users

        I am working on Sr2CoO4. Here I wanted to study the system with 
different spin state configuration of Co4+, which is known to be valence state 
of Co in this system. I could understand how to create:
            (a) High-spin configuration
            (b) Intermediate spin configuration
            (c) Low-spin configuration
        for the given Co atoms in the .inst file as

        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   (for HS state)
        and
        Co
        Ar 3
        3, 2,2.0  N
        3, 2,2.0  N
        3,-3,2.0  N
        3,-3,1.0  N
        4,-1,1.0  N
        4,-1,1.0  N  (for IS state)


        But my query is that .inst file takes Co as neutral atom (9
        electrons:3d74s2) and accordingly its spin state. As if Co were in 4+ 
state, I would have 5 electrons in 3d state (3d54s0) rather 9 electrons as is 
revealed from .inst file now.

        Please suggest me how to give spin state for Co4+ for this system.


        Thanks



        --
        *Komal*




    --
    *Komal*




--
*Komal*


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