[Wien] Is calculating the chemical shielding (orbital part) in paramagnetic system using x_nmr_lapw available ? x_nmr_lapw? lapwdm? DIPAN?
Peter Blaha
pblaha at theochem.tuwien.ac.at
Fri Jan 31 11:41:23 CET 2020
I can see that the (very small !!) difference comes solely from the
macroscopic susceptibility (NMRXIM).
We know that this term is not very stable in the calculations.
If you really need this precision, you have to increase anyway all
computational parameters to "infinity" (RKmax and k-mesh and lvns 6 or
even 8, and LM expansion to 8 or 10, GMAX=30, ...)
On 1/31/20 11:21 AM, 林敏 wrote:
> Dear Prof. Peter Blaha,
>
> Yes, I am calculating the Li+/Na+ NMR shifts in cathode of battery
> materials (usually transition metal oxide).
>
> Of course, most of Li+/Na+ NMR shifts is dominated by Fermi-contact
> shifts, which is related to :HFFxxx in the scf file.
>
> In some cases, the Fermi-contact shifts is small (several tens of ppm),
> so I don’t want to neglect the orbital shielding chemical shift casually
> even it’s range in several ppm.
>
> About the X_nmr, it do have -up/dn options. I test the program using
> LiCl: doing open shell SCF first, then running x_nmr -dn, x_nmr
> -up respectively.
>
> I get the same results, as follows:
>
> :NMRTOT001 ATOM: Li1 1 NMR(total/ppm) Sigma-ISO = 45.40
> Sigma_xx = 45.40 Sigma_yy = 45.40 Sigma_zz = 45.40
> :NMRASY001 ATOM: Li1 1 NMR(total/ppm) ANISO (delta-sigma) =
> -0.00 ASYM (eta) = 0.000 SPAN = 0.00 SKEW = 1.000
>
> :NMRTOT002 ATOM: Cl1 2 NMR(total/ppm) Sigma-ISO = 460.40
> Sigma_xx = 460.40 Sigma_yy = 460.40 Sigma_zz = 460.40
> :NMRASY002 ATOM: Cl1 2 NMR(total/ppm) ANISO (delta-sigma) =
> -0.00 ASYM (eta) = 0.000 SPAN = 0.00 SKEW = 1.000
>
> :NMRXIM NMR(macroscopic-component/ppm, trace(xi)*8*pi/3) = -5.33
>
>
> When I using x_nmr -dn -up, also the same results of x_nmr -dn , or
> x_nmr -up.
>
> While the close shell calculations get following results:
>
> :NMRTOT001 ATOM: Li1 1 NMR(total/ppm) Sigma-ISO = 90.24
> Sigma_xx = 90.24 Sigma_yy = 90.24 Sigma_zz = 90.24
> :NMRASY001 ATOM: Li1 1 NMR(total/ppm) ANISO (delta-sigma) =
> 0.00 ASYM (eta) = 0.000 SPAN = 0.00 SKEW = 1.000
>
> :NMRTOT002 ATOM: Cl1 2 NMR(total/ppm) Sigma-ISO = 920.24
> Sigma_xx = 920.24 Sigma_yy = 920.24 Sigma_zz = 920.24
> :NMRASY002 ATOM: Cl1 2 NMR(total/ppm) ANISO (delta-sigma) =
> -0.00 ASYM (eta) = 0.000 SPAN = 0.00 SKEW = 1.000
>
> :NMRXIM NMR(macroscopic-component/ppm, trace(xi)*8*pi/3) = -10.10
>
> which is not same as the sum of -dn and -up. What is the problem behind
> these?
>
> I can’t find further description of x_nmr on tutorial’s PPT and UG. Is
> there detail of -up and -dn options available?
>
> The dipole part of hyperfine interactions is used for simulation of NMR
> spectrum. I also meet some problem and I am checking the mail list.
>
> 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 <mailto:linmin at stu.xmu.edu.cn>
>
>
>
>
>
>> On Jan 28, 2020, at 4:38 PM, 林敏 <linmin at stu.xmu.edu.cn
>> <mailto:linmin at stu.xmu.edu.cn>> wrote:
>>
>> 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 <mailto: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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--
P.Blaha
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Peter BLAHA, Inst.f. Materials Chemistry, TU Vienna, A-1060 Vienna
Phone: +43-1-58801-165300 FAX: +43-1-58801-165982
Email: blaha at theochem.tuwien.ac.at WIEN2k: http://www.wien2k.at
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