[Pw_forum] Necessary to increase the number of interactions: NSTEP and NITER

[CLAUDIA BUNGARO]

Dear Wyllian,

niter=50 is usually more than enough to reach self consistency,
if you cannot reach convergence with 100 scf steps (niter)
there might be some problem in the way you describe your system.
You should check that all the other input parameters are appropriate
to describe your molecule.

 Things you may want to check, among others:

 That the electronic occupation scheme you are using is appropriate to
describe the electronic structure of your molecule you may need a
broadening (DEGAUSS!=0) and more bands (NBND), spin polarized calculation
for unpaired electrons (lsda=.true.)

 A smaller value of mixing parameter beta may help in some cases.


__________________________________________________
Dr. Claudia Bungaro
Dept. of Physics and Astronomy, Rutgers University
136 Frelinghuysen Road, Piscataway,  NJ 08854-8019

tel: +1 732 445 4197          fax: +1 732 445 4343
email: bungaro at physics.rutgers.edu
__________________________________________________


On Wed, 11 Jun 2003, [iso-8859-1] Wyllian Bezerra da Silva - WBS wrote:

> Greetings!
>
>
> Friends, please necessary to make more of the 100
> dynamic and electronic interactions. What I must make
> to increase the interactions. When I use to niter >
> 100 and nstep > 100, occurs error:
>
> IOS = 80
> %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
> from davcio : error #   99
> i/o error in davcio
> %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
> stopping ...
>
>
> Click in link below to see out of a citosina molecule:
>
>
> INPUT:
> http://www.biophysics.hpg.com.br/download/simulacoes/PWSCF/DNA/citosina/testes/citosina.in
>
> OUTPUT:
> http://www.biophysics.hpg.com.br/download/simulacoes/PWSCF/DNA/citosina/testes/citosina.out
>
>
>
> It could help me?
>
>
> Wyllian
>
>
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