[Pw_forum] relaxation

[Axel Kohlmeyer]

On Tue, 29 May 2007, Jess Kondor wrote:

JK> Hi Axel,
JK> 
JK> >
JK> > if you want to converge the geometry tightly, you have to converge
JK> > the wavefunction even more tightly. also, you may run into 'ripples',
JK> > particularly when using ultra-soft pseudopotentials.
JK> > in that case, you may also need to crank up the density cutoff.
JK> >
JK> >
JK> Thank you for suggestions, I'll try it. By the way, I use ecutwfc=35 Ry, and
JK> ecutrho=350 Ry, I think it was enough for ultrasoft PP.

it should be. it might depend on the pseudization parameters a little 
bit. and if you need high accuracy, you may need to crank up the 
wavefunction cutoff, too. 

cheers,
  axel.

JK> 
JK> cheers,
JK>   jess
JK> 

-- 
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Axel Kohlmeyer   akohlmey at cmm.chem.upenn.edu   http://www.cmm.upenn.edu
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