[ase-users] relaxation problem in the cluster model

[hayat hocine]

Dear ESA users mailing list
I want to fix three gold atoms and relax the copper atom (Cu) in the
CuAu3 cluster.
------------ the script

#!/usr/bin/env python
from ase import *
from ase.calculators.jacapo import *
from ase.lattice.surface import *
from ase.constraints import FixAtoms

import numpy as np

CuAu3 = Atoms([Atom('Au',[2.259749,3.880966,1.845724]),
             Atom('Au',[3.508997,1.692649,1.878040]),
             Atom('Au',[0.989053,1.704892,1.866603]),
             Atom('Cu',[2.087748,2.462808,3.699057])],
            cell=(8,8,8))
CuAu3.center()

mask = FixAtoms ([True,True,True,False])
CuAu3.set_constraint(mask)

calc = Jacapo('CuAu3-relax.nc',
               pw = 350,
               ft = 0.01,
               atoms = CuAu3)
qn = QuasiNewton (CuAu3, trajectory='CuAu3-relax.traj')
qn.run()

view(CuAu3)

E3 = CuAu3.get_potential_energy()
print E3
---------------------

Cordially

Hocine hayat