My Community

Posted: **Mon Feb 04, 2008 11:28 am**

In VASP manual I am bit confused with the GGA tag.
In LDA PAW POTCAR the default xc type is CA.If I write GGA = PE in the INCAR and use this LDA PAW POTCAR, am I doing a GGA calculation with PBE xc type?Please reply.

Posted: **Mon Feb 04, 2008 4:20 pm**

yes.
But why don't you use the paw-PBE potential if you want to use PBE-xc?

Posted: **Tue Feb 05, 2008 4:17 am**

I definitely can use pawPBE POTCAR, but I wanted to make myself clear on the basic tags used in VASP.
But I checked that if you do two calculations one with LDA potPAW POTCAR with GGA=91 in the INCAR and the other with potPAW_GGA POTCAR with nothing regarding GGA in the INCAR.So according to you these two must be identical calculations.But the total energy has significant deffernce between these two.Why is it so?