The mbj method and the volume optimization (from wien mailing list)

These are some recommendations to do volume optimization with the method mBJ:

1.

Hello,

When you use mBJ (number 28 in case.in0), the total energy is calculated
with LDA (i.e., the mBJ orbitals and electron density are plugged into
the LDA functional), and you can use this total energy for calculation of
energy vs. volume of unit cell. What is not possible, is to use forces for
the optimization of internal parameters. What do you mean by QW, QWR, QD?

Hybrid functionals similar to HSE are in WIEN2k, but I don't know when it
will be released into the distributed WIEN2k version:
http://arxiv.org/abs/1103.4466

F. Tran

Reference: https://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/msg04208.html 

2.

After force minimization with LDA or PBE, then do the mBJ calculation
without -fc. -fc is necessary if you do geometry optimization, which you
can not do with mBJ.

F. Tran

Reference: https://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/msg14797.html 

3.

But, beside this I do not recommend to do structure optimization with
TB-MBJ. Instead, you should do the structure optimization with a GGA
(e.g., WC or PBE) and then use TB-MBJ only for the optimized volume.
TB-MBJ is a potential which was developed for the band structure and not
for the geometrical properties.

F. Tran

Reference: https://www.mail-archive.com/wien@zeus.theochem.tuwien.ac.at/msg04346.html