The ABINIT Users Mailing List ( CLOSED )

[Martin Häufel <martin.haeufel@googlemail.com>]

Hi Jiang,

you can perform a cell optimization in two steps:

1. Optimization of the ionic positions only.

2. Full optimization of cell geometry, taking into account the symmetry.

# Dataset1: usual self-consistent ground-state calculation with
# optimization of ionic positions
ionmov1  2           # Conduct structural optimization
optcell1 0           # Optimization of the ionic positions only
ecutsm1  0.5         # Energy cutoff smearing
ntime1   50          # number of structural optimization steps

# Dataset2: self-consistent GS calculation with full optimization of
# cell geometry
ionmov2   2          # Conduct structural optimization
optcell2  2          # Full optimization of cell geometry
ecutsm2   0.5        # Energy cutoff smearing; when optcell/=0, ABINIT
                     # requires ecutsm to be larger than zero.
dilatmx2  1.1        # maximum dilatation
ntime2    50         # number of structural optimization steps
prtgeo2   1          # Print the geometry analysis

You can find more details in the documentation on the ABINIT website:
  http://www.abinit.org/documentation

Especially the notes on the varius input variables are helpful:

http://www.abinit.org/documentation/helpfiles/for-v5.8/input_variables/varrlx.html

Best regards,

Martin Haeufel
TU Munich, WSI (T33)
www.wsi.tum.de


On 27.01.2010 23:21, jiangx3@rpi.edu wrote:
> Hi everybody,
>
> I want to ask how to optimize a structure in abinit? I know the value of
> acell should be changed and xcart changes at the same time. I try to use
> the following method, but error comes out:
>
>
>
> ndtset   5  3
>
> acell:     1.4000 1.4000 20.0
> acell+    0.025 0.025 0.0
>           -0.025 0.025 0.0
> xangst:   0.0 0.0 0.0
>            1.4000 0.0 0.0
> xangst+   0.025 0.025 0.0
>           -0.025 0.025 0.0
>
>
> If anyone knows about the optimization in the abinit, would you please tell 
> me?