Hi In the following steps I want to become sure about understanding your answers. For checking my calculations I did as below 1. Performed scf calculations for my material with arbitary cell parameters(around experimental value), with fix but small k-points(8x8x1 for 2D sample). Then try to use different ecutwfc & its corresponding ecutrho to achieve convergency in energy 2. Then I used achievd ecutwfc & ecutrho in vc-rx to get optimized cell parameters & atomic positions. Again with small k-points. 3. Finally did scf calculation again with these calculated parameters & chech energy convergency vs k-points. you said that you have choose high ecutwfc or ecutrho (depend on your pps) in vc-rx .(?) if I do it would I have to use this high ecut wfc in other steps such as phonon calculations? By the way pbe pps are ultra soft but if you check C.pbe-van _bm.UPF you will see that suggested ecutwfc & ecut rho is 25,100 respectively(?) Best Regards Mehrnaz Iran University Of science & Technology -------------- next part -------------- An HTML attachment was scrubbed... URL: http://www.democritos.it/pipermail/pw_forum/attachments/20090602/2587b3e5/attachment.htm
