[Pw_forum] (no subject)
prasenjit.jnc at gmail.com
Tue Apr 7 16:43:35 CEST 2009
ecutwfc determines the size of the plane wave you are using for your cal.
(Note that PWscf is a plane wave based code, i.e., the wave functions are
expanded in a plane wave basis).
If you use ultrasoft pseudopotential, you introduce augmentation charges
(because norm-conserving condition is not satisfied by these pp's). For
those one uses ecutrho.
In your case you are using norm-conserving pseudopotentials. Therefore for
ecutrho you can use the default value (ecutrho=4*ecutwfc). However, it is
better to use ultrasoft PP because you need lower value of ecutwfc, i.e.,
fewer no. of plane waves and therefore faster calculations.
There are plenty of good books & papers available. Please go through them
before you do the cal. or ask ur questions in the forum. Also look into the
manual & the mailing list archive.
PS: Don't forget to add ur affiliation.....its a netiquette for this forum.
2009/4/7 Dimpy Sharma <dimpy.sharma at tyndall.ie>
> Can anyone please explain me the significance of ecutwfc and ecutrho in
> quantum espresso input file. And what is the diffeence between these two
> Pw_forum mailing list
> Pw_forum at pwscf.org
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