SOC structural relaxation

[juihung_hung]

On the VASP manual, it suggests using a non self-consistent run for SOC calculation.
However, does SOC ever effect the structure and does doing a self-consistent run with ion relaxation makes any sesnse?

[andreas.singraber]

Hello!

I am sorry but your question is unclear to me. Can you please add more background and detail to your question? Where exactly you see contradictions in the VASP documentation (please cite the pages and chapters to look at)?

Best,

Andreas Singraber

[juihung_hung]

I am calculating a system with tantalum.

I am wondering if SOC will effect the lattice constant.
I have two approach

1)
follow by LSORBIT tag https://www.vasp.at/wiki/index.php/LSORBIT
do a collinear run then do a non self-consistent run.

2) if SOC will largely affect the lattice constant
I first do a collinear run.
and adding the SOC relative tags, however with ion relaxation.


with optB86b-vdW the c lattice constant is 5.9320827 without SOC and 7.85 with SOC
but with using PBE + vdw https://www.vasp.at/wiki/index.php/IVDW using all the default and test out all the corrections.
the c lattice constant differs less than 0.01

Here, I am confused