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Which is my ecutwfc converged value in this calculation result.

How to choose ecutrho in quantum espresso calculation.

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2 Answers 2

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Convergence is always defined in term of tolerance what user choose and based on your data, I will take ecutwfc as 70 Ryd. You should also report run time along with these data. For considering ecutrho I will suggest you to stick with default value, if you are dealing with metallic system.

Kinetic energy cutoff (Ry) for charge density and potential: For norm-conserving pseudopotential you should stick to the default value, you can reduce it by a little but it will introduce noise especially on forces and stress. If there are ultrasoft PP, a larger value than the default is often desirable (ecutrho = 8 to 12 times ecutwfc, typically). PAW datasets can often be used at 4*ecutwfc, but it depends on the shape of augmentation charge: testing is mandatory. The use of gradient-corrected functional, especially in cells with vacuum, or for pseudopotential without non-linear core correction, usually requires an higher values of ecutrho to be accurately converged.

References:

https://www.quantum-espresso.org/Doc/INPUT_PW.html#idm274

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You can choose E-E_best value to be less than 0.01 eV (magnitude) per atom. The E_best is the highest ecutwfc (110 Ry) you considered.

So 40 Ry is a rough idea to consider, seeing your results. Though you need to do the kpoint convergence as well to get final decision.

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