My Community

Dear all,
I have couple questions about GGA calculation.
1. I would like to do GGA=PE for bulk calculation and my INCAR looks like as follows.

System = bulk calculation
ISTART = 0
ICHARG= 2
ENCUT = 400
ISMEAR = -5
SIGMA = 0.2
LEXCHG = 5
GGA = PE

dynamic:
IBRION = 2
ISIF = 2
NSW = 200

The POTCAR is come from pot_gga.( In the POTCAR, LEXCH = 91.) Am I right?

2. What the LEXCHG and LEXCH standard for?

3. Can I do GGA = PW or LM or PB for calculation? If I can, what the LEXCHG number is for GGA = PW or LM or PB?


Any advice will be appreciated!

please use the PBE POTCAR if you want to use PE XC, you don't have to get the GGA tag in INCAR explicitely then.

Dear Sir,
I have checked our POTCAR library and I find that we just have pot and pot_gga. In pot library, the LEXCH = CA in the POTCAR. In pot_gga library, the LEXCH = 91 in the POTCAR. So, we have not the PBE POTCAR in our POTCAR library. Am I right? If so, how can have the PBE POTCAR?

Thanks so much!

the PBE potentials are only available in the PAW -PP data base.

the PBE potentials are only available in the PAW -PP data base.