[Pw_forum] Nickel surface calculations

[Axel Kohlmeyer]

ameya,

please check the mailing list archives first. similar reports
have been sent in (and replied to) before.

it looks as if your geometry optimization has problems
to converge. your convergence threshold for the SCF
is pretty large. it should to be smaller by about two
orders of magnitude than the convergence parameters
for the geometry.

cheers,
    axel.

On 8/22/06, Ameya Joshi <ajoshi at mines.edu> wrote:
>
>
> Hello all,
>
> Attached is my input file for relaxing the (111) surface for Nickel. The run
> ended with an error message, that I fail to understand. Heres the last part
> of the output:
>
> *******************************************************************************
>
>
> number of scf cycles = 23
>
> number of bfgs steps = 11
>
> energy old = -257.0883841977 ryd
>
> energy new = -257.0883839659 ryd
>
> CASE: energy_new > energy_old
>
> new trust radius = 0.0000499952 bohr
>
> trust_radius < trust_radius_min
>
> resetting bfgs history
>
> %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
>
> from bfgs : error # 1
>
> bfgs history already reset at previous step
>
> %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
>
> stopping ...
>
> *******************************************************************************
>
> I checked the previous step in the output and found that the bfgs history
> was reset at the previous step too (as the error message says). Can anyone
> please explain what this means and a way to remedy this ? Just for
> information, the geometry and energy was almost converged by the end of the
> run.
>
> Thanks,
>
> Ameya Joshi
>


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