Dear Davide, Thank you very much for this. I will try to do some more digging into this issue. It seems to me elk is the way to go, since wien2k is commercial and I have no access to it .
I have one more question about gipaw with DFT+U. If I am only interested in chemical shift, is gipaw fully functional with DFT+U, for both norm-conserving and ultra-soft pesudopotentials? Does DFT+U type in pwscf matter for gipaw? I noticed some issues in calculations, but I would like to know what the code is supposed to do at this stage before reporting it. Cheers On Mon, Oct 9, 2017 at 8:13 AM, Davide Ceresoli <[email protected]> wrote: > Dear Jia, > I have to admit that this is the first time that NMR/EFG results > depend so much on the choice of the pseudopotential. I've calculated > a bunch of minerals, both with NC and US pseudos, and results are > in good agreement each other. > > I've tested several Co pseudos (NC, NC+semicore, PAW+semicore) on > Co3O4 spinel and the EFG results span the entire real numbers range, > both for Co and for O. > > Which one is correct? I don't know. I'm in favor of pseudopotentials > with semicore states. They should be closer to all-electron. > > Do you have some reference with Co EFG calculated all-electron (wien2k, > elk/exciting) on some simple system? If not, is there someone that > could help us to setup a wien2k/elk calculation? > > Best regards, > Davide > > > > > > On 09/20/2017 06:50 PM, Jia Chen wrote: > >> Dear All, >> >> I am working on calculating nmr parameters with gipaw code. I have two >> settings: one with norm-conserving gipaw pesudopotentials which has some >> semi-core states, and the other with ultra-soft gipaw pseudopotentials. >> Electronic structure eigenvalues from pwscf look similar, and >> chemical-shift are not far away from each other. The issue is quadrupolar >> coupling, for Co, norm-conserving calculation gives 0.5MHz and ultra-soft >> gives 1.5MHz. It seems to me a significant discrepancy. I don't know what >> caused the inconsistency, and which one is more reliable. I appreciate any >> insight on this problem. >> >> One thing about norm-conserving calculation is that the code gives >> warming about some orbitals has zero norm. I don't know if that could be of >> concern. >> >> Cheers >> Jia >> >
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