I have been trying to optimize a bulk CuO using PBE and PBEsol with D3. I've tried GPW and GAPW with various combinations of basis sets, kpoints and broken symmetry and have not been able to match the optimized geometry from VASP.
The goal is to study adsorption onto the CuO surface. I'm wondering, if I constrain the CuO slab in the experimentally determined coordinates and cell length/angles, if the adsorption results would be trustworthy?
Overall, I must admit, that I'm somewhat surprised and disappointed in CP2K's lack of ability to match both experimentally and calculated results. So again, my real question is, can the results be trusted, given that I have been unable to recreate the first step of the process?