TersoffZBLPotential¶

class TersoffZBLPotential(particleType1, particleType2, type, Z1, Z2, a0, rf, bf)¶

Constructor of the potential.

Note: TersoffSingleTypePotentials must be added for BOTH particle types!

Parameters:

particleType1 (ParticleType or ParticleIdentifier) – Identifier of the first particle type.
particleType2 (ParticleType or ParticleIdentifier) – Identifier of the second particle type.
type (int) – either 1 or 2, sets the type of the actual potential
Z1 (float) – Potential parameter.
Z2 (float) – Potential parameter.
a0 (PhysicalQuantity of type length) – Potential parameter.
rf (PhysicalQuantity of type length) – Potential parameter.
bf (PhysicalQuantity of type length**-1) – Potential parameter.

classmethod getAllParameterNames()¶: Return the names of all used parameters as a list.

getAllParameters()¶: Return all parameters of this potential and their current values as a <parameterName / parameterValue> dictionary.

static getDefaults()¶: Get the default parameters of this potential and return them in form of a dictionary of <parameter name, default value> key-value pairs.

getParameter(parameterName)¶: Get the current value of the parameter parameterName.

setParameter(parameterName, value)¶

Set the parameter parameterName to the given value.

Parameters:

parameterName (str) – The name of the parameter that will be modified.
value – The new value that will be assigned to the parameter parameterName.

Usage Examples¶

Define a Tersoff potential for gold by adding particle types and interaction functions to the TremoloXPotentialSet.

# -------------------------------------------------------------
# Bulk configuration for FCC gold
# -------------------------------------------------------------

# Set up lattice
vector_a = [4.07825, 0.0, 0.0]*Angstrom
vector_b = [0.0, 4.07825, 0.0]*Angstrom
vector_c = [0.0, 0.0, 4.07825]*Angstrom
lattice = UnitCell(vector_a, vector_b, vector_c)

# Define elements
elements = [Gold, Gold, Gold, Gold]

# Define coordinates
fractional_coordinates = [[ 0.0,  0.0,  0.0],
                          [ 0.5,  0.5,  0.0],
                          [ 0.5,  0.0,  0.5],
                          [ 0.0,  0.5,  0.5]]

# Set up configuration
bulk_configuration = BulkConfiguration(
    bravais_lattice=lattice,
    elements=elements,
    fractional_coordinates=fractional_coordinates
    )

# -------------------------------------------------------------
# Calculator
# -------------------------------------------------------------

# Create a new potential set
potentialSet = TremoloXPotentialSet(name='Tersoff_Au_2012')

# Add the particle type to the potential set
potentialSet.addParticleType(ParticleType(symbol='Au',
                                          mass=196.967*atomic_mass_unit))

# Add the single type potential to the potential set
potentialSet.addPotential(TersoffSingleTypePotential('Au',
                                                     A=5445.22104118*eV,
                                                     B=247.287913089*eV,
                                                     R=3.0*Angstrom,
                                                     S=3.4*Angstrom,
                                                     l=3.13294032317/Angstrom,
                                                     mu=1.60663606317/Angstrom,
                                                     alpha=2.05/Angstrom,
                                                     beta=1.0,
                                                     omega=0.0006374494,
                                                     chi=1.0,
                                                     chiR=1.0,
                                                     m=1,
                                                     n=1.0,
                                                     c=3.351525,
                                                     d=0.1649262,
                                                     h=-0.9941884))

# Add the ZBL modification to the potential set
potentialSet.addPotential(TersoffZBLPotential('Au', 'Au',
                                              type=1,
                                              Z1=79.0,
                                              Z2=79.0,
                                              a0=0.529*Angstrom,
                                              rf=1.7*Angstrom,
                                              bf=12.0/Angstrom))

# Create the TremoloX calculator from the potential set
calculator = TremoloXCalculator(parameters=potentialSet)

bulk_configuration.setCalculator(calculator)