[Wien] spin configuration for charge state

[Laurence Marks]

The first BVS number is for the lattice you used, the second is an
approximate estimate for an expanded lattice with the typical PBE
expansion. You can/should put into a file ".latcalib" (note the "." at the
front) the linear expansion/contraction for the DFT optimized volume.

The numbers you have are a bit odd, particularly the Sr is rather high. Did
you take the positions from some report of SrCoO2.5 or are you just
calculating the metastable SrCoO3? If a phase is metastable (or unstable)
you cannot expect it to yield "simple" results such as a Co4+ valence. The
Sr-Co-O family is quite complex.

On Thu, May 12, 2016 at 4:44 AM, Komal Bapna <komal.bapna at gmail.com> wrote:

> Dear Prof. Peter and Laurence,
>
> I am really thankful for your valuable suggestions.
>
> *Prof. Laurence::*
>
> These are the bond-valence sums, I am getting
> Atom   1 equiv  1 Sr         Bond-Valence Sum     2.40    2.58
> Atom   2 equiv  1 Co         Bond-Valence Sum     3.03    3.20
> Atom   3 equiv  1 O O1       Bond-Valence Sum     2.25    2.39
> Atom   4 equiv  1 O O2       Bond-Valence Sum     1.67    1.78
>
> Please tell the two values in each line. Can I now say that these are the
> valence state for respective atom. If it is so, why for Co it is not 4!!!!
>
>
> *Prof. Peter:: *
>
> I tried 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.
> For Co up spin
>          0.89437  0.00000  0.00000  0.00000 -0.04204
>          0.00000  0.93434  0.00000  0.00000  0.00000
>          0.00000  0.00000  0.91726  0.00000  0.00000
>          0.00000  0.00000  0.00000  0.93434  0.00000
>         -0.04204  0.00000  0.00000  0.00000  0.89437
> Total spin moment: 4.57467
> For Co dn spin
>          0.34200  0.00000  0.00000  0.00000 -0.05202
>          0.00000  0.33947  0.00000  0.00000  0.00000
>          0.00000  0.00000  0.34654  0.00000  0.00000
>          0.00000  0.00000  0.00000  0.33947  0.00000
>         -0.05202  0.00000  0.00000  0.00000  0.34200
> Total spin moment: 1.70947
>
> Total energy is 516 meV greater than the previous case.
> SPIN MAGNETIC MOMENTS OF MIXED CHARGE DENSITY
> INTERSTITIAL  =    0.14578
>   Sr =    0.00800
> Co =    2.89880
> O1 =    0.23087
> O2 =    0.17575
> total moment in the CELL  =    3.87383
>
> Looking at the moments, can I say Co is in high spin state, as the moment
> is still low than its actual theoretical high spin moment (~5 muB).
>
> Thanks and Regards
>
> On Tue, May 10, 2016 at 5:24 PM, Komal Bapna <komal.bapna at gmail.com>
> 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.bapna at 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.bapna at 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*
>>
>
>
>
> --
> *Komal*
>



-- 
Professor Laurence Marks
"Research is to see what everybody else has seen, and to think what nobody
else has thought", Albert Szent-Gyorgi
www.numis.northwestern.edu ; Corrosion in 4D: MURI4D.numis.northwestern.edu
Partner of the CFW 100% program for gender equity, www.cfw.org/100-percent
Co-Editor, Acta Cryst A
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://zeus.theochem.tuwien.ac.at/pipermail/wien/attachments/20160512/af85190c/attachment.html>
-------------- next part --------------
_______________________________________________
Wien mailing list
Wien at zeus.theochem.tuwien.ac.at
http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien
SEARCH the MAILING-LIST at:  http://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/index.html