Hubbard-U Term, Spin Polarization and Geometry Optimization

[berna]

Hi.
If we use Hubbard-U parameter (LDA-U, GGA-U) for dft calculation, should dft for  geometry optimization include Hubbard-U parameter?
Similar as above,  if we use spin polarization for dft calculation, should dft for  geometry optimization include  spin polarization?

[Jess Wellendorff]

Depends on the system, but one does not in general use DFT-U for geometry optimization. On the contrary, including the spin-polarization in geometry optimization of a ferromagnetic material like iron is crucial.

[Kim_W]

1. NO, NO2, and O2 are paramagnetic, should dft for  geometry optimization include spin-polarization?
2. If we calculate heavy elements, should dft for  geometry optimization include spin-polarization?

[Daniele Stradi]

Yes, in principle the geometry optimization and electronic structure calculation on the optimized geometry should be done at the same level of theory