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17O NMR calculation

Posted: Tue Jul 02, 2019 9:28 am
by farahnaz.mlk
Hi everybody!

I'm using VASP for calculation of 17O chemical shift in oxides. My problem is that in some cases the chemical shielding of all oxygen anions in the slab (bulk and surface) shifted more than 100 ppm. I repeat the calculations on different machines with different compilers, smaller EDIFFs, higher cutoffs and KPOINTS, different ISMEAR and SIGMA, adsorbed molecule in both sides of the slab, but the problem doesn't solve.
I also consider the EFG in the calculations that the QUAD_EFG value is correct.

these are the flags that I'm using:

EDIFF = 1E-7
ALGO = Normal
PREC = A
LREAL = .FALSE.
IBRION = 2
IVDW = 12
ISMEAR = 0
SIGMA = 0.05

Chemical Shift :
LCHIMAG = .TRUE.
DQ = 0.001
ICHIBARE = 1
LNMR_SYM_RED = .TRUE.
NLSPLINE = .FALSE.
LEFG = .TRUE.
QUAD_EFG = -25.58 0 0

All the best

Farahnaz

Re: 17O NMR calculation

Posted: Wed Sep 11, 2024 3:11 pm
by support_vasp

Hi,

We're sorry that we didn’t answer your question. This does not live up to the quality of support that we aim to provide. The team has since expanded. If we can still help with your problem, please ask again in a new post, linking to this one, and we will answer as quickly as possible.

Best wishes,

VASP