def test_dimer_method(testdir):
    # Set up a small "slab" with an adatoms
    atoms = fcc100('Pt', size=(2, 2, 1), vacuum=10.0)
    add_adsorbate(atoms, 'Pt', 1.611, 'hollow')

    # Freeze the "slab"
    mask = [atom.tag > 0 for atom in atoms]
    atoms.set_constraint(FixAtoms(mask=mask))

    # Calculate using EMT
    atoms.calc = EMT()
    atoms.get_potential_energy()

    # Set up the dimer
    with DimerControl(initial_eigenmode_method='displacement',
                      displacement_method='vector',
                      logfile=None,
                      mask=[0, 0, 0, 0, 1]) as d_control:
        d_atoms = MinModeAtoms(atoms, d_control)

        # Displace the atoms
        displacement_vector = [[0.0] * 3] * 5
        displacement_vector[-1][1] = -0.1
        d_atoms.displace(displacement_vector=displacement_vector)

        # Converge to a saddle point
        with MinModeTranslate(d_atoms,
                              trajectory='dimer_method.traj',
                              logfile="dimer_method.log") as dim_rlx:
            dim_rlx.run(fmax=0.001)
Пример #2
0
def test_dimer_method():
    # Set up a small "slab" with an adatoms
    atoms = fcc100('Pt', size=(2, 2, 1), vacuum=10.0)
    add_adsorbate(atoms, 'Pt', 1.611, 'hollow')

    # Freeze the "slab"
    mask = [atom.tag > 0 for atom in atoms]
    atoms.set_constraint(FixAtoms(mask=mask))

    # Calculate using EMT
    atoms.set_calculator(EMT())
    atoms.get_potential_energy()

    # Set up the dimer
    d_control = DimerControl(initial_eigenmode_method = 'displacement', \
                             displacement_method = 'vector', logfile = None, \
                             mask = [0, 0, 0, 0, 1])
    d_atoms = MinModeAtoms(atoms, d_control)

    # Displace the atoms
    displacement_vector = [[0.0] * 3] * 5
    displacement_vector[-1][1] = -0.1
    d_atoms.displace(displacement_vector=displacement_vector)

    # Converge to a saddle point
    dim_rlx = MinModeTranslate(d_atoms, trajectory = 'dimer_method.traj', \
                               logfile = None)
    dim_rlx.run(fmax=0.001)

    # Test the results
    tolerance = 1e-3
    assert (d_atoms.get_barrier_energy() - 1.03733136918 < tolerance)
    assert (abs(d_atoms.get_curvature() + 0.900467048707) < tolerance)
    assert (d_atoms.get_eigenmode()[-1][1] < -0.99)
    assert (abs(d_atoms.get_positions()[-1][1]) < tolerance)
Пример #3
0
# Relax the initial state:
QuasiNewton(initial).run(fmax=0.05)
e0 = initial.get_potential_energy()

traj = Trajectory('dimer_along.traj', 'w', initial)
traj.write()

# Making dimer mask list:
d_mask = [False] * (N - 1) + [True]

# Set up the dimer:
d_control = DimerControl(initial_eigenmode_method='displacement',
                         displacement_method='vector',
                         logfile=None,
                         mask=d_mask)
d_atoms = MinModeAtoms(initial, d_control)

# Displacement settings:
displacement_vector = np.zeros((N, 3))
# Strength of displacement along y axis = along row:
displacement_vector[-1, 1] = 0.001
# The direction of the displacement is set by the a in
# displacement_vector[-1, a], where a can be 0 for x, 1 for y and 2 for z.
d_atoms.displace(displacement_vector=displacement_vector)

# Converge to a saddle point:
dim_rlx = MinModeTranslate(d_atoms, trajectory=traj, logfile=None)
dim_rlx.run(fmax=0.001)

diff = initial.get_potential_energy() - e0
print(('The energy barrier is %f eV.' % diff))
Пример #4
0
                  'trial_angle': pi / 4.0,
                  'trial_trans_step': 0.001,
                  'maximum_translation': 0.1,
                  'cg_translation': True,
                  'use_central_forces': True,
                  'dimer_separation': 0.0001,
                  'initial_eigenmode_method': 'gauss''displacement',
                  'extrapolate_forces': False,
                  'displacement_method': 'gauss''vector,
                  'gauss_std': 0.1,
                  'order': 1,
                  'mask': None, # NB mask should not be a "parameter"
                  'displacement_center': None,
                  'displacement_radius': None,
                  'number_of_displacement_atoms': None}"""
    d_atoms = MinModeAtoms(runner, d_control)
    """# Enable with 'displacement' - 'vector'
    # Displacement settings:
    # initial vector:
    displacement_vector = np.zeros((N, 3))
    # Strength of displacement along y axis = along row:
    displacement_vector[-1, 0] = 0.1
    # The direction of the displacement needed if usint displacement vector method 
    # displacement_vector[-1, a], where a can be 0 for x, 1 for y and 2 for z.
    d_atoms.displace(displacement_vector=displacement_vector)"""

    # Converge to a saddle point:
    dim_rlx = MinModeTranslate(d_atoms,
                               trajectory=traj)  # , logfile=None)
    dim_rlx.run(fmax=0.001)
Пример #5
0
atoms = fcc100('Pt', size = (2, 2, 1), vacuum = 10.0)
add_adsorbate(atoms, 'Pt', 1.611, 'hollow')

# Freeze the "slab"
mask = [atom.tag > 0 for atom in atoms]
atoms.set_constraint(FixAtoms(mask = mask))

# Calculate using EMT
atoms.set_calculator(EMT())
relaxed_energy = atoms.get_potential_energy()

# Set up the dimer
d_control = DimerControl(initial_eigenmode_method = 'displacement', \
                         displacement_method = 'vector', logfile = None, \
                         mask = [0, 0, 0, 0, 1])
d_atoms = MinModeAtoms(atoms, d_control)

# Dispalce the atoms
displacement_vector = [[0.0]*3]*5
displacement_vector[-1][1] = -0.1
d_atoms.displace(displacement_vector = displacement_vector)

# Converge to a saddle point
dim_rlx = MinModeTranslate(d_atoms, trajectory = 'dimer_method.traj', \
                           logfile = None)
dim_rlx.run(fmax = 0.001)

# Test the results
tolerance = 1e-3
assert(d_atoms.get_barrier_energy() - 1.03733136918 < tolerance)
assert(abs(d_atoms.get_curvature() + 0.889396) < tolerance)
# dimer setup
dimer_control = DimerControl(initial_eigenmode_method='displacement',
                             displacement_method='vector',
                             maximum_translation=0.2,
                             trial_trans_step=5.0e-3,
                             dimer_separation=dimer_dist,
                             mask=d_mask,
                             f_rot_min=0.01,
                             f_rot_max=0.2,
                             trial_angle=pi / 4,
                             max_num_rot=2,
                             logfile='%s_control.log' % prefix,
                             eigenmode_logfile='%s_eigenmode.log' % prefix)

dimer_atoms = MinModeAtoms(dimer, dimer_control, eigenmodes=[mode])
dimer_atoms.displace(displacement_vector=mode)

dimer_relax = MinModeTranslate(dimer_atoms,
                               trajectory='%s.traj' % prefix,
                               logfile='%s_relax.log' % prefix)
# also possible to use these:
#dimer_relax = FIRE(dimer_atoms, trajectory='dimer.traj',
#                   restart='restart_file',
#                   dt=0.1, # default 0.1
#                   maxmove=0.2, # default 0.2
#                   dtmax=1.0, # default 1.0
#                   Nmin=3, # default 5
#                   finc=1.1, # default 3
#                   fdec=0.71, # default 0.5
#                   astart=0.2, # default 0.1
Пример #7
0
# Relax the initial state:
QuasiNewton(initial).run(fmax=0.05)
e0 = initial.get_potential_energy()

traj = Trajectory('dimer_along.traj', 'w', initial)
traj.write()

# Making dimer mask list:
d_mask = [False] * (N - 1) + [True]

# Set up the dimer:
d_control = DimerControl(initial_eigenmode_method='displacement',
                         displacement_method='vector',
                         logfile=None,
                         mask=d_mask)
d_atoms = MinModeAtoms(initial, d_control)

# Displacement settings:
displacement_vector = np.zeros((N, 3))
# Strength of displacement along y axis = along row:
displacement_vector[-1, 1] = 0.001
# The direction of the displacement is set by the a in
# displacement_vector[-1, a], where a can be 0 for x, 1 for y and 2 for z.
d_atoms.displace(displacement_vector=displacement_vector)

# Converge to a saddle point:
dim_rlx = MinModeTranslate(d_atoms,
                           trajectory=traj,
                           logfile=None)
dim_rlx.run(fmax=0.001)
atoms = fcc100("Pt", size=(2, 2, 1), vacuum=10.0)
add_adsorbate(atoms, "Pt", 1.611, "hollow")

# Freeze the "slab"
mask = [atom.tag > 0 for atom in atoms]
atoms.set_constraint(FixAtoms(mask=mask))

# Calculate using EMT
atoms.set_calculator(EMT())
relaxed_energy = atoms.get_potential_energy()

# Set up the dimer
d_control = DimerControl(
    initial_eigenmode_method="displacement", displacement_method="vector", logfile=None, mask=[0, 0, 0, 0, 1]
)
d_atoms = MinModeAtoms(atoms, d_control)

# Displace the atoms
displacement_vector = [[0.0] * 3] * 5
displacement_vector[-1][1] = -0.1
d_atoms.displace(displacement_vector=displacement_vector)

# Converge to a saddle point
dim_rlx = MinModeTranslate(d_atoms, trajectory="dimer_method.traj", logfile=None)
dim_rlx.run(fmax=0.001)

# Test the results
tolerance = 1e-3
assert d_atoms.get_barrier_energy() - 1.03733136918 < tolerance
assert abs(d_atoms.get_curvature() + 0.900467048707) < tolerance
assert d_atoms.get_eigenmode()[-1][1] < -0.99