# What parameters have to converge before doing a relax calculation?

I am a beginner of Quantum Espresso. I have taken 221 MoS2 Monolayer and done a relax calculation. In case of bulk system, or any doping in supercell, which is preferred: vc-relax or relax? It's not clear to me under what conditions I need to use one vs the other.

Before the relax calculation, I converged ecutwfc, k-points and ecutrho (using ultrasoft pseudopotential). Do any other parameters have to converge before starting this type of calculation?

• This is your answer for first part mattermodeling.stackexchange.com/questions/2358/… For relaxed structure energy and energetics of doping, convergence of K-point, ecutwfc, ecutrho is sufficient Jul 5 at 2:25
• Thankyou for the answer Jul 6 at 16:26

Prior to any production calculation, the convergence study with ecutwfc, k-points and ecutrho should be enough. But, the better should be to do a convergence study using the property you are interested in.