pV calculation using pstress
Moderators: Global Moderator, Moderator
pV calculation using pstress
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?
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?
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- Global Moderator
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- Joined: Mon Nov 18, 2019 11:00 am
Re: pV calculation using pstress
Hi,
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