[Wien] GaP NMR chemical shift question

[Jing-Han Chen]

Hi, Robert

  Thank you for your suggestion. I did use TETRA for GaP chemical
shift calculation. The TEMP Fermi method in case.in2 does improve the
result much better. However, we found that different values of TEMP
with the same kbT size give different chemical shielding. Should we
use the same value of TEMP in case.in2 as in metal option? If not, do
you have any recommendation?

2014-04-21 1:29 GMT-05:00 Robert Laskowski <rolask at ihpc.a-star.edu.sg>:
> Hi,
>
> the metal option works only with TEMP Fermi method in in2. Maybe you have TETRA, in this case Fermi level is shifted by 0.5 Ry, leading to wrong shielding.
>
> regards
>
> Robert
>
>
>
> On 18 April 2014 AM 11:07:27 Jing-Han Chen wrote:
>> Dear WIEN2k users
>>
>>   We tried to use NMR package to verify GaP chemical shift. It has
>> been known to be a semiconductor and is fcc with one Ga at (0,0,0)and
>> one P at (1/4,1/4,1/4). We tried to use default and metal option to
>> obtain Sigma-ISO and it gave us a surprising difference as the
>> following(110000 k points)
>>
>> ==> default option <==
>>
>> :NMRTOT001  ATOM:       Ga   1  NMR(total/ppm) Sigma-ISO =   1353.09
>>   Sigma_xx =   1353.09   Sigma_yy =   1353.09   Sigma_zz =   1353.09
>> :NMRASY001  ATOM:       Ga   1  NMR(total/ppm) ANISO (delta-sigma) =
>>    0.00     ASYM (eta) = 0.000     SPAN =      0.00     SKEW = 1.000
>>
>> :NMRTOT002  ATOM:        P   2  NMR(total/ppm) Sigma-ISO =    377.85
>>   Sigma_xx =    377.85   Sigma_yy =    377.85   Sigma_zz =    377.85
>> :NMRASY002  ATOM:        P   2  NMR(total/ppm) ANISO (delta-sigma) =
>>    0.00     ASYM (eta) = 0.000     SPAN =      0.00     SKEW = 1.000
>>
>> ==> metal option <==
>>
>> :NMRTOT001  ATOM:       Ga   1  NMR(total/ppm) Sigma-ISO =   2704.12
>>   Sigma_xx =   2704.12   Sigma_yy =   2704.12   Sigma_zz =   2704.12
>> :NMRASY001  ATOM:       Ga   1  NMR(total/ppm) ANISO (delta-sigma) =
>>    0.00     ASYM (eta) = 0.000     SPAN =      0.00     SKEW = 1.000
>>
>> :NMRTOT002  ATOM:        P   2  NMR(total/ppm) Sigma-ISO =   1082.72
>>   Sigma_xx =   1082.72   Sigma_yy =   1082.72   Sigma_zz =   1082.72
>> :NMRASY002  ATOM:        P   2  NMR(total/ppm) ANISO (delta-sigma) =
>>    0.00     ASYM (eta) = 0.000     SPAN =      0.00     SKEW = 1.000
>>
>>   The difference is more than 1000ppm for Ga atom. We do this test
>> since we want to understand how metal option works and the proper
>> usage/parameters.
>>
>>   Any suggestion and comment are appreciated.
>>
>>
> --
> ==================================================
> Dr. Robert Laskowski
>
> Senior Scientist, Materials Science & Engineering Department
> Institute of High Performance Computing, A*STAR
> 1 Fusionopolis Way, #16-16, Connexis, Singapore 138632
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-- 
Jing-Han Chen
Graduate Student
Department of Physics
Texas A&M University
4242 TAMU
College Station TX  77843-4242
jhchen at tamu.edu <jhchen at tamu.edu> / http://people.physics.tamu.edu/jhchen/