The application of U parameter and SO effect for 3d and 4d elements (Chemist answer)

Answering a question about the application of the DFT+U+SO method, a chemist made this statement.

Re: [Wien] LDA+U +SOC calculations

Xavier Rocquefelte Tue, 20 Mar 2018 10:14:32 -0700

Dear Sylwia

I will give you a chemist answer, which appears to work properly in many cases.

If you have 3d elements, the crystal field (CF) is usually larger than SOC, thus I will do first orb, and then include SO.

If you have 4f elements, the SOC is usually larger than the CF, thus I will do first SO and then add orb.

It is not a general recipe. It must be adapted to the system and you have to try.

Best Regards

Xavier

Reference: https://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/msg17190.html