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from ase import Atoms, Atom
from ase.build import fcc111
from ase.optimize.minimahopping import MinimaHopping
from ase.calculators.emt import EMT
from ase.constraints import FixAtoms, Hookean
# Make Pt 111 slab with Cu2 adsorbate.
atoms = fcc111('Pt', (2, 2, 1), vacuum=7., orthogonal=True)
adsorbate = Atoms([Atom('Cu', atoms[2].position + (0., 0., 2.5)),
Atom('Cu', atoms[2].position + (0., 0., 5.0))])
atoms.extend(adsorbate)
# Constrain the surface to be fixed and a Hookean constraint between
# the adsorbate atoms.
constraints = [FixAtoms(indices=[atom.index for atom in atoms if
atom.symbol == 'Pt']),
Hookean(a1=4, a2=5, rt=2.6, k=15.),
Hookean(a1=4, a2=(0., 0., 1., -15.), k=15.)]
atoms.set_constraint(constraints)
# Set the calculator.
calc = EMT()
atoms.set_calculator(calc)
# Instantiate and run the minima hopping algorithm.
hop = MinimaHopping(atoms,
Ediff0=2.5,
T0=2000.,
beta1=1.2,
beta2=1.2,
mdmin=1)
hop(totalsteps=3)
# Test ability to restart and temperature stopping.
hop(maxtemp=3000)
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