My Community

Dear all,

I am trying to simulate the pressure effect using pstress=100 kB, then I am confused about the pV term calculation in OUTCAR. In OUTCAR, it gives stress,
external pressure = 220.19 kB Pullay stress = 100.00 kB
and energy:
energy without entropy= -22.77508611 energy(sigma->0) = -22.78062274
enthalpy is TOTEN = -12.57957370 eV P V= 10.20658568

The volume of cell: is 163.53

From all those data, I evaluate that the value of pV term (10.2065) is calculated using p=100kB (Pullay stress) NOT p= 220.19 (external pressure) + 100 (Pullay stress). I am wondering why VASP ignores the effect of the external pressure (220.19) in the calculation of pV? It seems that the external pressure should affect the total enthalpy a lot. Can I trust the enthalpy especially during the geometric relaxation?

Hi,

We're sorry that we didn’t answer your question. This does not live up to the quality of support that we aim to provide. The team has since expanded. If we can still help with your problem, please ask again in a new post, linking to this one, and we will answer as quickly as possible.

Best wishes,

VASP