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from ase import Atom, Atoms
from ase.build import fcc110
from ase.calculators.emt import EMT
from ase.constraints import FixAtoms, Hookean
from ase.optimize.minimahopping import MinimaHopping
# Make the Pt 110 slab.
atoms = fcc110('Pt', (2, 2, 2), vacuum=7.0)
# Add the Cu2 adsorbate.
adsorbate = Atoms(
[
Atom('Cu', atoms[7].position + (0.0, 0.0, 2.5)),
Atom('Cu', atoms[7].position + (0.0, 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=8, a2=9, rt=2.6, k=15.0),
Hookean(a1=8, a2=(0.0, 0.0, 1.0, -15.0), k=15.0),
]
atoms.set_constraint(constraints)
# Set the calculator.
calc = EMT()
atoms.calc = calc
# Instantiate and run the minima hopping algorithm.
hop = MinimaHopping(atoms, Ediff0=2.5, T0=4000.0)
hop(totalsteps=10)
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