[Wien] Is calculating the chemical shielding (orbital part) in paramagnetic system using x_nmr_lapw available ? x_nmr_lapw? lapwdm? DIPAN?

[Peter Blaha]

So you seem to look for Na or Li-NMR results ?

For a spin-polarized case, x_nmr needs -up or -dn
But I do not remember, if we ever tried it, but in principle it should work.
If it is a Li+ or Na+ it will be very similar to the reference material 
and not provide the main effect.

In any case, you seem to look for a transfered hyperfine field and the 
main contribution will be the contact term (coming from the 4s TM atoms, 
reaching to the Na-nucleus. Check :HFFxxx in the scf file.

You can of course also calculate the dipol term using lapwdm (on a Na+ 
it should be very small) and the external dipol term using dipan (also 
here, my guess it that it is very small (check convergence with distance 
in dipan - a lattice sum is hard to converge in direct space), unless 
your structure has a very anisotropic environment around Na/Li.



Am 28.01.2020 um 16:38 schrieb 林敏:
> Dear Prof. Peter Blaha,
> 
> Thank you very much for your reply.
> 
> Very sorry for confusing you.
> 
> Here, the paramagnetic system, I mean the open shell system or spin polarize calculation, specifically is transition metal oxide, which usually are insulator/semiconductor.
> 
>  From your reply, I still suppose that x_nmr doesn’t work for such system. The error message is no case.vsp file, while I have   case.vsp(up/dn).
> 
> About the dipole part, what I want to calculate is the hyperfine interaction between transition metal ions (TM) and observed nucleus (Li+/ Na+...), rather than TM nucleus themselves. The isotropic part is very easy done in normal SCF calculations. But the dipole part, can the magnetic field of TM be seen as external field for observed nucleus ? So I have to use DIPAN?
> Right?
> 
> Best regards,
> 
> Min
> ———————————————
> Min Lin
> 2018 Ph. D student
> Physical Chemistry
> Chemistry Department Chemistry & College of Chemistry and Chemical Engineering
> Xiamen University
> China
> e-mail: linmin at stu.xmu.edu.cn
> 
> 
> 
> 
> 
>> On Jan 27, 2020, at 6:04 PM, 踢球者 <2236673859 at qq.com> wrote:
>>
>> Dear Wien experts,
>>
>> Is calculating the chemical shielding (orbital part) in paramagnetic system using x_nmr_lapw available ?
>>
>> I suppose not after reading the UG carefully.
>>
>> I find that, there is a program in WIEN2k, lapwdm.
>>
>> "RINDEX=3 LSINDEX=3: <X> is the orbital part of the hyperfine field at the nucleus (for a converged calculation at the very end)"
>> Is this for chemical shielding ?
>>
>> By the way, in this program: RINDEX=3 LSINDEX=5: <X> is the spin dipolar part of the hyperfine field at the nucleus (for a converged calculation at the very end). Here, what is the difference between DIPAN program doing and "spin dipolar part of the hyperfine field" ?
>>
>> About the DIPAN. Why I have to input spin moments of atoms?  Why not calculating using spin density directly?
>>
>> Best wishes,
>>
>> Min
> 
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Peter BLAHA, Inst.f. Materials Chemistry, TU Vienna, A-1060 Vienna
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