[Wien] NMR calculation in Spin-polarized cases

[Carlier Dany]

Dear Mitsunori Nakamoto,
I beleive that the NMR module implemented in wein2k concerns only the 
calculation of the chemical shift and not the Fermi contact shift. Is is 
therefore normal to find a value close to the one of LiCl, since the 
chemical shift range for Li in diamagnetic compounds is really narrow. 
In order to compute the Fermi contact shift, in a spin polarized 
calculation, you should use the HFF (hyperfine field) value linked to 
the electronic spin density at the nucleus and also the experimental 
magnetic susceptibility in order to compute the Fermi contact shift at 
the temperature of the NMR experiment.
You can see also refs :

*NMR study of the LiMnPO_4 .OH and MPO_4 .H_2 O (M = Mn, V) homeotypic 
phases and DFT calculations*

A. Castets, D. Carlier, Y. Zhang, F. Boucher, N. Marx, R. Gautier, E. Le 
Fur, L. Le Pollès, L. Croguennec, and M. Ménétrier

/Solid State NMR, special issue: //Solid State NMR of Materials for 
Energy Storage and Conversion/, 2012, 42, 42--50.

*Multinuclear NMR and DFT calculations on the LiFePO_4 .OH and FePO_4 
.H_2 O homeotypic phases*

A. Castets, D. Carlier, Y. Zhang, F. Boucher, N. Marx, L. Croguennec, 
M. Ménétrier

/J. Phys. Chem. C/, 2011, 115, 16234-16241.

//**Regards
Dany Carlier

On 13/11/2013 11:20, Nakamoto, Mitsunori wrote:
> Dear WIEN2k users and developers,
>
> I'm Mitsunori, an engineer in Sony. I'm interested in calculating NMR contact shifts by using the NMR module recently implemented in WIEN2k (v13). I have a question about NMR calculations in spin-polarized cases.
>
> First, the calculations on a paper (Phys Rev B 85, 245117) were tested, and the results were confirmed to be reproduced. Then I moved on shift calculations in more complicated materials, for example, Li6CoO4 as shown in a paper (Phys Chem C 116 27393, it seems they don't use the NMR module in WIEN2k). I expected to obtain similar values also by the NMR module, but it failed. The obtained ppm value for Li in Li6CoO4 is almost same as that in LiCl (reference material), which means the shift is nearly 0.
>
> My SCF calculation is the spin-polarized one and the result shows that the electronic state is as expected (S=6 per unit cell by -up setup). DOS is same as the one in the paper above. I wonder if my calculation procedure for NMR shifts is correct or not. My procedure is as follows:
>
>   x_nmr_lapw -mode in1 -nodes ** -up -p -scratch /scr/**up/
>   x_nmr_lapw -up -p
>
> This procedure is repeated for -dn in another directory by using the same SCF result. I mean,
>
>   x_nmr_lapw -mode in1 -nodes ** -dn -p -scratch /scr/**dn/
>   x_nmr_lapw -dn -p
>
> Then I summed up ppm values from these calculations. Is this a right way or not? Is there any important parameters as for this type of calculation?
> Any advice would be appreciated. Thank you in advance.
>
> Mitsunori Nakamoto
> Mitsunori.Nakamoto at jp.sony.com
> Sony Corporation
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>    


-- 
Mme Dany CARLIER-LARREGARAY
ICMCB-CNRS
Maître de conférences - Université Bordeaux1
33 +5 40 00 35 69

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