[Pw_forum] Defining an antiferromagnetic graphene nanoribbon

[Nicola Marzari]

Roberto G. A. Veiga wrote:
> Hi, Stefano:
> 
> as far as I understand, if I use a cutoff for a system made of carbons 
> and I find it is appropriate, I should use the same cutoff for another 
> system also made of carbons. I mean, if I use 20 Ry for carbon nanotubes 
> and the results are fine, I could use 20 Ry for diamond, or graphene. Is 
> it wrong my assumption?


The convergence tests for ultrasoft carbon are actually posted on the
webpage:

http://www.quantum-espresso.org/pseudo/upfdetails.php?upf=C.pbe-rrkjus.UPF

Interesting, sp2 carbon (graphite) looks a bit smoother than
sp3 carbon (diamond) (I do wonder why) but roughly the cutoffs
are the same.

				nicola


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