the copper (111) surface lattice constant

[njuxyh]

Hi:
i use the database in atk to use the copper bulk geometry, and then cleave it to select (111) surface as the electrodes
and then i want to relax the surface, so a issues come out,
if i choose five layer surfaces, and i only want to relax the atomic positions the first two layers, other five layers are fixed, how i set in the input file?

and my thinkings about to deal the copper(111) surface as the electrode are correct?

ps, any one has relaxed the copper(111) surface in atk? or is there a data source to obtain the copper(111) surface information?

i need your help !

thanks

[zh]

You should first optimize the lattice constant of bulk copper before cleaving it to construct the surface structure.

After that, do the constraint geometry optimization of the surface structure  of copper with the calculated lattice constant. To fix the atoms in the first two or three topmost layers, one needs to specify the corresponding atoms index in "OptimizeGeometry(..., constraints=[....],)". Please refer to the manual for the detailed information: http://quantumwise.com/documents/manuals/latest/ReferenceManual/index.html/ref.optimizegeometry.html