Free electronic energy, outdata
Posted: Thu Oct 03, 2013 6:05 pm
Hi!
I've used VASP to calculate the free electronic energy (at T>0 K, of course), but I'm not sure about the outdata. The free electronic energy is given by
Fel=Eel-TSel
(see e.g. http://www.sciencedirect.com/science/ar ... 5404000965). Naturally, one would thus think that
Fel=F-E0,
i.e., the difference between the total free energy and the energy for sigma -> 0. However, in the OUTCAR file one finds a term ENTROPY TSel which is (except for a factor of 2) equal to F-E0. Also, in the VASP manual it is stated that TSel is indeed F-E0. I've therefore got two questions:
1) Is Eel included in TSel in VASP without mention?
2) Why is TSel=2(F-E0) in OUTCAR? Where does the factor 2 come from?
I've used VASP to calculate the free electronic energy (at T>0 K, of course), but I'm not sure about the outdata. The free electronic energy is given by
Fel=Eel-TSel
(see e.g. http://www.sciencedirect.com/science/ar ... 5404000965). Naturally, one would thus think that
Fel=F-E0,
i.e., the difference between the total free energy and the energy for sigma -> 0. However, in the OUTCAR file one finds a term ENTROPY TSel which is (except for a factor of 2) equal to F-E0. Also, in the VASP manual it is stated that TSel is indeed F-E0. I've therefore got two questions:
1) Is Eel included in TSel in VASP without mention?
2) Why is TSel=2(F-E0) in OUTCAR? Where does the factor 2 come from?