[Wien] (no subject)
Rocquefelte
Xavier.Rocquefelte at cnrs-imn.fr
Wed Apr 18 17:19:36 CEST 2012
Have you got any interesting experimental data to compare your
calculations and then have a better idea of the U value?
The U value is not only dependent of the element and orbital, but also
on the dimensionality and interactions (covalency) of the compound.
I would then say that the choice of the U value is always matter of
experience. You can also have a look at the note of G. Madsen and P.
Novak, which is on the WIEN2K website:
http://www.wien2k.at/reg_user/textbooks/
- Notes about constraint LDA calculations to determine U (pdf)
Regards
Xavier
On 04/18/2012 01:59 PM, Madhav Ghimire wrote:
> Dear Dr. Xavier,
> Thank you very much for your prompt reply and for your useful
> comments. Now I understand how it works.
> For the Platinates or iridates because of their extended orbitals, the
> U value is small as explained from literature. So basing on the
> literatures, I choose 1-2 eV. to check the nature of band structure.
> Do you think it to be very small. If so please let me know upto how
> much i can use.
> Will there be any influence if U=5 eV for this type of compound is
> chosen. Of course, at high U with inclusion of spin-orbit coupling, it
> shows interesting behavior in band structure. But I fail to plot the
> fat bands in band structure to identify spin up and spin down together.
> By the way, Do you know whether we can fix the value of magnetic
> moment of Pt along any specified direction.
> If so, I would like to know how and in which file.
> Thanks again.
> best wishes
> M. P. Ghimire
>
> 2012/4/18 Rocquefelte <Xavier.Rocquefelte at cnrs-imn.fr
> <mailto:Xavier.Rocquefelte at cnrs-imn.fr>>
>
> I didn't look in detail your email but here is the solution.
>
> You should use the following case.indm file:
>
> --------------------------
>
> -9. Emin cutoff energy
> 2 number of atoms for which density matrix
> is calculated
> 4 1 2 index of 1st atom, number of L's, L1
> 5 1 2 dtto for 2nd atom, repeat NATOM times
> 0 0 r-index, (l,s)index
> --------------------------
>
> and case.inorb file:
>
> --------------------------
>
> 1 2 0 nmod, natorb, ipr
> PRATT 1.0 BROYD/PRATT, mixing
> 4 1 2 iatom nlorb, lorb
> 5 1 2 iatom nlorb, lorb
> 1 nsic 0..AFM, 1..SIC, 2..HFM
> 0.1471 0.036 U J (Ry) Note: we recommend to use U_eff
> = U-J and J=0
> 0.1471 0.036 U J
> --------------------------
>
> To explain, let's take an example:
>
>
> 4 1 2 index of 1st atom, number of L's, L1
>
> Here you are saying that you will add a Hubbard term for atom 4,
> and only for one l-value, which is l = 2.
> This treatment will be applied to the valence state of Pt, i.e.
> the 5d orbital of Pt. You should not specify the principal quantum
> number in this file (n-value).
>
> I hope this reply will clarify the situation.
>
> Regards
>
> Xavier
>
> P.S.1: It is recommended to use a Ueff value, i.e. Ueff = U -J.
> In you case it will correspond to the following case.inorb file:
>
>
> --------------------------
>
> 1 2 0 nmod, natorb, ipr
> PRATT 1.0 BROYD/PRATT, mixing
> 4 1 2 iatom nlorb, lorb
> 5 1 2 iatom nlorb, lorb
> 1 nsic 0..AFM, 1..SIC, 2..HFM
> 0.1435 0.000 U J (Ry) Note: we recommend to use U_eff
> = U-J and J=0
> 0.1435 0.000 U J
> --------------------------
>
> P.S.2: The Hubbard term you are using is quite small (2eV). Is it
> what you really need for your system?
>
>
>
>
>
> On 04/18/2012 01:14 PM, Madhav Ghimire wrote:
>> Dear Dr. Xavier and wien users,
>> Thank you for your kind concern to my problem. Sorry for the
>> incomplete information. Let me complete my few queries and cases
>> over which I am concerned to:
>> (i) I am having one oxide compound with the presence of Pt atoms
>> having 5d states. Because of this, I want to implement U. For the
>> said case, we require case.indm and case.inorb as suggested in
>> userguide. My edited case.indm file is as shown below
>> -9. Emin cutoff energy
>> 2 number of atoms for which density matrix
>> is calculated
>> 4 2 5 index of 1st atom, number of L's, L1
>> 5 2 5 dtto for 2nd atom, repeat NATOM times
>> 0 0 r-index, (l,s)index
>> In this indm file (marked with red color), I could not understand
>> how L's=1 and , L1=2 is taken in userguide. From the the
>> userguide, L's corresponds to number of l-values for which the
>> density matrix should be calculated and L1 is the l-values for
>> which the density matrix should be calculated.
>> For the case of Pt which is 5d atom it has l=2 and n=5 with d=5
>> sublevels. Hence I substituted as shown above. But, I did not
>> understand whether L's must be 2 or 5. Similar is for the case of
>> L1. And, what about the r-index.
>> (ii) For case.inorb, below is the input value I tried to use
>> 1 2 0 nmod, natorb, ipr
>> PRATT 1.0 BROYD/PRATT, mixing
>> 1 2 5 iatom nlorb, lorb
>> 2 2 5 iatom nlorb, lorb
>> 1 nsic 0..AFM, 1..SIC, 2..HFM
>> 0.1471 0.036 U J (Ry) Note: we recommend to use U_eff
>> = U-J and J=0
>> 0.1471 0.036 U J
>> As in case.indm, I have similar type of problem. As mentioned in
>> userguide,
>> nlorb; number of orbital moments for which exact exchange shall
>> be calculated
>> lorb: orbital numbers .
>> Here, I could not differentiate between the number of orbital
>> moments and orbital numbers. Does it mean the same or they are
>> different.
>> Could you kindly help to correct this two files.
>> (iii) Can we fix the orbital moment of Pt.
>> (iv) Can we set the minimum energy to more than 400 eV as the
>> ground state energy of oxygen is approx. 400 eV.
>>
>> Thank you in advance
>> M. P. Ghimire
>> NIMS, Japan
>>
>> 2012/4/18 Rocquefelte <Xavier.Rocquefelte at cnrs-imn.fr
>> <mailto:Xavier.Rocquefelte at cnrs-imn.fr>>
>>
>> It seems that your message is incomplete.
>> However, I am surprized to see nlorb = 5!
>>
>> If you are interested in "d" orbitals, nlorb should be 2, and
>> if it is "f" orbitals, nlorb should be 3.
>>
>> Best Regards
>>
>> Xavier
>>
>>
>>
>>
>>
>> On 04/18/2012 09:26 AM, Madhav Ghimire wrote:
>>>
>>> Dear wien2k users,
>>> I am facing some problems in putting the value of n
>>> nlorb and lorb as provided in userguide.
>>> -9. Emin cutoff energy
>>> 2 number of atoms for which density
>>> matrix is calculated
>>> 4 2 5 index of 1st atom, number of L's, L1
>>> 5 2 5 dtto for 2nd atom, repeat NATOM times
>>> 0 0 r-index, (l,s)index
>>> for
>>> --
>>> M. P. Ghimire
>>>
>>>
>>> _______________________________________________
>>> Wien mailing list
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>>> http://zeus.theochem.tuwien.ac.at/mailman/listinfo/wien
>>
>>
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>>
>>
>>
>>
>> --
>> M. P. Ghimire
>>
>>
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>> Wien mailing list
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>
>
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>
>
>
>
> --
> M. P. Ghimire
>
>
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