[Pw_forum] choosing ecutwfc through vc-rx

[Mehrnaz Anvari]

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
 
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