I'm calculating the total energy at the ACFDT-RPA level using VASP in terms of this tutorial. For the first three steps it uses:

ISMEAR = 0 ; SIGMA = 0.05

but for the final step does not use these parameters. I think there it takes default parameters. Does it make difference?

  • $\begingroup$ The default value of ISMEAR is 1: vasp.at/wiki/wiki/index.php/ISMEAR $\endgroup$
    – Jack
    Dec 23, 2020 at 8:26
  • $\begingroup$ Hi Savir, I suggest you edit the question title to add a little more info about what you intend to ask. "ISMEAR and SIGMA" makes it sound too general. $\endgroup$ Dec 23, 2020 at 22:29

1 Answer 1


Strictly speaking, you should be consistent and use the same smearing approach and smearing width for all calculations on a given structure. It has the potential to influence the (extrapolated, 0 K) energy, although the differences are likely to be minor. They probably just forgot to include the flags in the input file for that final calculation, but I'd recommend keeping them for consistency.

The defaults are ISMEAR=1 and SIGMA=0.2, which is quite different. If the energy is at all sensitive to SIGMA, then you may notice a slight difference in energies depending on which flags are used.


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