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REPLAY:Work Function, Alpha+beta Term and XC:(G=0)
Posted: Fri Jul 12, 2024 11:22 am
by KWH
Back in 2017 someone asked about the meaning of E-Fermi, XC(G=0), and alpha+beta in the OUTCAR file as they relate to the actual Fermi energy used in the calculation of work function from the LOCPAR file. It appears this question was never answered. Can someone please help with a definition of these three terms and how they are correctly used?
Re: REPLAY:Work Function, Alpha+beta Term and XC:(G=0)
Posted: Fri Jul 12, 2024 4:14 pm
by alexey.tal
Hi,
XC(G=0) is the G=0 component of the exchange-correlation potential. Alpha is related to the G=0 component of the pseudopotential. Beta is related to the G^2 term in the Taylor expansion of the atomic charge densities.
These terms are explained in
J Ihm et al., J. Phys. C: Solid State Phys. 12 4409 (1979) and their origin in VASP was explained
here.
These terms should not be included in the calculation of the work function. Please see our tutorial on the work function calculation
here.