[Wien] [SUSPECTED SPAM] Re: [SPAM] Re: Forward of moderated message

[pboulet]

All right, I am going to do that.

Thank you.
Pascal



> Le 7 mars 2021 à 22:16, Peter Blaha <pblaha at theochem.tuwien.ac.at> a écrit :
> 
> Forget kram at the moment.
> Check case.joint if this file looks ok. It contains the unbroadened imag epsilon (eps2).
> It should be zero up to the band gap, but increase afterwards.
> 
> Check the band ranges in case.scf2
> You will see how far it reaches in energy above EF.
> 
> PS:   Hybrid DFT calculations:
> 
> Since hybrid DFT is expensive, it is VERY important to check convergence of various parameters, starting with SMALL parameters.
> 
> Eg. a scf calculation with 12x12x12 full k-mesh is almost certainly an overkill.  If this is a semiconductor, I'd start with 4x4x4 and later check it.
> 
> There is a good reason that we offer the "reduced k-mesh" It saves a lot of time. Maybe for beginning a 2x2x2 mesh is fine as a start.
> 
> Number of bands: As L. Marks said: maybe the technical minimum NB+1 is missleading in the UG. This is certainly not converged. I would add start with adding 2-3 bands/atom in the unit cell. If you have 9 atoms/cell, add 20-30 bands at the beginning. ( This depends a lot on the type of atom. You should always add all empty orbitals of an atom (all d-orbitals of a TM atom, or all p for C or Si, P, S ....)
> 
> Once you have a result for optics, increase (double) these parameters and check how much the optics has changed.
> 

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