[Wien] two questions about NMR calculations

Robert Laskowski rolask at ihpc.a-star.edu.sg
Mon Oct 28 09:33:24 CET 2013


If you sum the :NMRTOT from energy windows, the result should be equal to the total shielding. The same concerns NMRSPH. It these does not sum up it may indicate that there is a problem with the code or you are missing some states in the sum. The difference between NMRTOT and NMRSPH gives the contribution from the interstitial region.



regards



Robert



On 28 October 2013 PM 3:30:58 Bing Zhou wrote:

> Dear Robert,

>

> It is so great to have the response from you, I have carefully read your

> series publications about NMR chemical shift calculations using WIEN2k on

> Physical Review B, which are so helpful.

>

> Using the borate mineral of probatite (CaNa[B5O7(OH)4].3H20) as an example,

> I am going to investigate the magnetic shielding mechanism at the five B

> sites in it by decomposing the chemical shifts into different energy

> windows. These energy windows include core states (<-3.6), Na/2s (-3.6,

> -3.5), Ca/3s (-2.8, -2.6), Na/2p (-1.5, -1.45), Ca/3p & O/2s (-1.45, -1.1),

> B/2s (-0.7, -0.45), B/2p & Na/3s, Ca/43 and O/2p (>-0.45). Of course, I

> also calculated the contributions from the energy window gaps between them,

> which usually are very close to 0.0000.

>

> At the same time, I also obtained the chemical shifts (":NMRTOTxxx) at each

> B sites from the energy window of (-infinity, +infinity) by running

> "x_nmr_lapw".

>

> I tabulated the data of ":NMRTOTxxx" from the above different energy windows

> using "x_nmr_lapw -emin xx -emax yy". However, the ":NMRTOTxxx" from

> (-infinity, +infinity) is not equal the summation of ":NMRTOTxxx" from the

> above windows such as core states, Na/2p, B/2s, O/2p, B/2p etc. There

> exists a systematic differenece around 11 ppm between the summation and

> that for (-infinity, +infinity), may I interpret such a difference as the

> interestial contributions for the chemical shifts?

>

> On the other hand, the summations of ":NMRTOTxxx" from the above energy

> windows also deviate from the corresponding summations of ":NMRSPHxxx" as

> expected, may I also explain such deviations as from the interestial

> contributions?

>

> In one word, I am a begainner for such a NMR study, I am desperate for your

> helps, I hope you don't mind giving me further helps when you are

> available.

>

> Thank you again!

>

> Bing

>

>

>

>

> --------------------------------------------

> On Sun, 10/27/13, Robert Laskowski <rolask at ihpc.a-star.edu.sg> wrote:

>

> Subject: Re: [Wien] two questions about NMR calculations

> To: "A Mailing list for WIEN2k users" <wien at zeus.theochem.tuwien.ac.at>

> Received: Sunday, October 27, 2013, 8:49 PM

>

> Hi,

> energy is in Ry. Did you included core contribution to the

> total shielding?

> It is excluded when emin is specified.

>

> regards

>

> Robert

>

> On 28 October 2013 AM 8:25:37 Bing Zhou wrote:

> > Dear all,

> >

> > I try to decompose the magnetic shielding contributions

>

> into different

>

> > energy windows using DOS, here I have two questions in

>

> running

>

> > "x_nmr_lapw":

> >

> > Question 1 is about the additivity of the NMR shielding

>

> contributions from

>

> > different energy windows: I assume the summation for

>

> the shielding

>

> > contributions from each energy windows should be equal

>

> to the total

>

> > chemical shielding calculated. However, it seems not

>

> that case, i.e., the

>

> > summation did not add up to the total shielding

>

> calculated, am I right or

>

> > did I miss something?

> >

> > Questions 2 is simply about the energy unit used for

>

> energy window of DOS:

> > there are two energy units (eV and Ry) for DOS map,

>

> however, what is the

>

> > default energy unit in running "x_nmr_lapw -emin xx

>

> -emax yy"? "xx" and

>

> > "yy" are in the unit of Ry?

> >

> > Thank you in advance!

> >

> > Bing

> >

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>

> --

> ==================================================

> Dr. Robert Laskowski

>

> Senior Scientist, Materials Science & Engineering

> Department

> Institute of High Performance Computing, A*STAR

> 1 Fusionopolis Way, #16-16, Connexis, Singapore 138632

> Tel(Off): +65. 64191493     Fax: +65.

> 64632536

> =================================================

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--

==================================================

Dr. Robert Laskowski



Senior Scientist, Materials Science & Engineering Department

Institute of High Performance Computing, A*STAR

1 Fusionopolis Way, #16-16, Connexis, Singapore 138632

Tel(Off): +65. 64191493 Fax: +65. 64632536

=================================================

IHPC Values :: Impact :: Honesty :: Performance :: Co-operation
This email is confidential and may be privileged. If you are not the intended recipient, please delete it and notify us immediately. Please do not copy or use it for any purpose, or disclose its contents to any other person. Thank you.
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