[Pw_forum] hyperfine calculation

[Jones Tsz-Kai Wan]

Dear Davide,

I read the post before. I guess we actually have two problems: the
Fermi-contact term and dipole-dipole term. Regarding the Fermi contact
term, can you send me the code you mentioned so that I give it a try?
Also, I don't think that the core-relaxation would completely cancel
the dipole-dipole term.

Regards,

Jones

On Wed, Dec 9, 2009 at 3:01 AM, Davide Ceresoli <ceresoli at mit.edu> wrote:
> Jones Tsz-Kai Wan wrote:
>> Dear pwscf users
>>
>> Does anyone here have experience on HF calculation using gipaw?
>>
>> I made extensive test on hyperfine tensor calculation using the gipaw
>> code, and I couldn't get reasonable result except free hydrogen atom.
>> For H atom, the Fermi contact term (A_s) obtained (~1480) is within
>> 10% of published work [e.g. Van de Walle and Blochl, PRB 47, 4244
>> (1993)]. However, the results for Si is unreasonable. The Fermi
>> contact is only ~ 1% of the published data, and the dipole term (A_p)
>> is zero, which is impossible.
>>
>> Jones Wan
>>
>> Published result:
>> A_s ~ 1400 for H, A_s ~ -4200 and A_p ~ -100 [Van de Walle, PRB 47,
>> 4244 (1993)].
> Dear Jones Wan,
>     because in Si the spin-density comes from p orbitals. The exchange
> potential generated by the p orbitals, polarizes slightly the 3s orbital,
> strongly the 2s electrons, which are not included in the pseudopotential.
> One has to perform the core-relaxation. For further details, see the
> following post:
> http://www.democritos.it/pipermail/pw_forum/2009-September/014475.html
>
> Davide
>
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