My Community

When I want to to do a GGA calculation what is the difference between the following two cases----
1.Using POTPAW POTCAR and Writing GGA= PE in the INCAR file.
2.Using POTPAW_GGA POTCAR and do not specifying GGA tag in the INCAR file.
So other than exchange correlation,is there any difference in the above two cases?And in the second case what should be the exchage correlation to be taken as default?

if you specify GGA=PE, a Perdew-Burke-Ernzerhof XC type will be used, otherwise Perdew-Wang 91, which is the default XC for with POTPAW_GGA

That's good.So if I want to do a GGA calculation with Perdew-Burke-Ernzerhof XC type, which POTCAR should I use?is it POTPAW or POTPAW_GGA?In POTPAW POTCAR default XC type is CA and that of in POTPAW_GGA is 91?Is it that with GGA =PE in the INCAR both the POTCAR will give the identical result?Please specify.I am a bit confused...

If you want to do a GGA calculation with PBE XC type within PAW theme, you should choose POTPAW_PBE POTCAT. Wish help.