# Smearing values for different codes

I am using Quantum Espresso along with a different code, I am performing calculations on Platinum bulk.

After choosing the "cold" smearing (which I read is a good choice for metals) with a value of ~ 0.009 Ry (~ 0.1292 eV, ~ 1500 K). I have been told: "The natural way is Fermi-Dirac and 1500 K is way too big. Please use Fermi-Dirac and a lower value so that we can compare it with the other code"

So now I use Fermi-Dirac with 0.0038 Ry (0.0517 eV, 600 K), but I see some c_bands: X eigenvalues not converged

I read here and there that Fermi-Dirac with metals should be used with high values, typically between 0.2 eV and 0.5 eV.

Is it possible that a code would need a bigger smearing value than another one? That would explain why this person told me this?

• It may help to include references for why cold smearing is a good choice for metals and why Fermi-Dirac smearing should use a large parameter.
– Tyberius
Oct 29 at 18:30
• Make sure that you know whether the "smearing" input is interpreted as the standard deviation of the broadening function, or the full-width half-maximum. Also, when comparing "cold" smearing results, make sure you're using the same Hermite polynomial expansion. Nov 22 at 1:22