My Community

Dear VASP community,

It is known from the literature that monoclinic alpha-phase of solid oxygen forms antiferromagnetic molecular crystal with ferromagnetic O2 molecules.

I have obtained the antiferromagnetic solution by standard PBE relaxation (with the tag LMAXMIX=4) of this structure, attached *.PBE files. The spin-polarized non-collinear setup lowered energy by approx. 100meV/at. compared to the non-spin-polarized one.

I wanted to start HSE06 spin-polarized relaxation from the already relaxed PBE structure from the final PBE-spin state. I was not able to do that with the LMAXMIX=4 tag, however (the job even did not started to run). Hence I was forced to remove this line, files *.HSE06 enclosed, leading to somewhat different structure: monoclinic angle beta 116deg. instead of 120deg. and zero magnetic state with HSE06 (and ferromagnetic PBE-state without LMAXMIX=4 line).

Is there any way to correctly reproduce the antiferromagnetic O2 state with HSE06?

Eva Pospisilova

Dear Eva,

Thank you for your message. I'm sorry for not replying so slowly. I missed it with the new year. I'll look into it now.

Best wishes,

Chris

Dear Eva,

I'm afraid that we couldn't repeat your results. Is there any particular reason that you're using the LMAXMIX tag? We obtained antiferrimagnetic structures using MAGMOM = 1.0 1.0 -1.0 -1.0 for PBE and HSE06. Your k-point mesh seems rather dense, which might create some issues. Generally, we recommend starting with a smaller k-point mesh to relax and then increasing the k-point mesh density later. Is calculating ferromagnetic O2 your end goal or is this an initial calculation for building towards some larger calculations? This would make it easier for us to understand your calculation goals.

Best wishes,

Chris