The ABINIT Users Mailing List ( CLOSED )

["Anglade Pierre-Matthieu" <anglade@gmail.com>]

PS: Because your goal is  cell optimisation you don't need such a
drastic criterion as "tolvrs 1e-18" for SCF convergence. You'd better
use something like toldff = [0.1-0.01]*tolmxf.
Moreover tolmxf  is probably much too small. Even with 1e-6 or 1e-5
you will get a perfectly converged system; likely more converged than
the absolute precision allowed by your k-point and ecut.

On 9/14/07, Anglade Pierre-Matthieu <anglade@gmail.com> wrote:
> Hi,
>
> 1) Instead of "pulayit" use "npulayit" which I think is the correct form
> 2) use "iprcel 45" for instance
> 3) if your geometry is too far from equilibrium, instead of CG for the
> ion movement prefer a MD-viscous damping for some iterations.
>
> regards
>
> PMA
>
> On 9/14/07, david.hendry@mandmd.com.au <david.hendry@mandmd.com.au> wrote:
> > Dear Abinitians,
> >
> > I'm trying to relax a single unit cell of CaTiO3 with two Ca removed and 
> > one Sm added.  The geometry does not converge fast enough: after 200 
> > nsteps the potential residual is still above 1.  Each ntime step 
> > therefore only marginaly reduces the atomic forces.  The input file is 
> > added below.  I'm using Troullier-Martins norm-conserving psps.  Might 
> > there be some way to allow this to work more efficiently?
> >
> > Regards,
> >
> > David.
> >
> >
> > #Definition of lattice parameters
> > #********************************
> >   acell  10.1629 14.4451 10.2329
> >
> > #Definition of atomic positions and types
> > #****************************************
> >    natom       19
> >    ntypat      4
> >    znucl       22 20 62 8
> >    typat       1 1 1 1 2 3 3 4 4 4 4 4 4 4 4 4 4 4 4
> >    xred        0      0     0.5
> >                0.5    0     0
> >                0      0.5   0.5
> >                0.5    0.5   0
> >                0.9937 0.25  0.03339
> >                0.5063 0.75  0.53339
> >                0.4937 0.25  0.46661
> >                0.0707 0.25  0.4842
> >                0.4293 0.75  0.9842
> >                0.9293 0.75  0.5158
> >                0.5707 0.25  0.0158
> >                0.711  0.037 0.2884
> >                0.789  0.963 0.7884
> >                0.289  0.537 0.7116
> >                0.211  0.463 0.2116
> >                0.289  0.963 0.7116
> >                0.211  0.037 0.2116
> >                0.711  0.463 0.2884
> >                0.789  0.537 0.7884
> >
> >
> >
> > #Echange-correlation functional
> > #******************************
> >    ixc         1
> >
> > #Plane wave basis and k-point grid
> > #*********************************
> >    #pawecutdg   60
> >    ecut        42
> >    ngkpt       7 5 7
> >    nshiftk     1
> >    shiftk      0.5 0.5 0.5
> >    nband       53
> >    ngfft       60  90  60
> >
> > #Relax ions and unit cell
> > #************************
> >     #chkprim    0
> >     kptopt     1
> >     iscf       7
> >     pulayit    20
> >     tolvrs     1.0d-18
> >     tolmxf     1.0d-8
> >     nstep      200
> >     optcell    0
> >     ionmov     3
> >     ntime      200
> >     dilatmx    1.1
> >     ecutsm     0.5
> >     prtwf      0
> >     prtden     0
> >
>
>
> --
> Pierre-Matthieu Anglade
>


-- 
Pierre-Matthieu Anglade