ReferenceChemicalPotential

class ReferenceChemicalPotential(element, internal_energy=None, entropy=None, reference_temperature=None)

A class defining the chemical potential for an atomic species.

Parameters:

  • element (PeriodicTableElement) – The element for which the atomic chemical potential is defined.

  • internal_energy (PhysicalQuantity of type energy) – The internal energy per atom of the specified element in some reference configuration.
    Default: 0*eV.

  • entropy (PhysicalQuantity of type energy per temperature) – The entropy per atom of the specified element in some reference configuration.
    Default: 0*eV/Kelvin.

  • reference_temperature (PhysicalQuantity of type temperature) – Temperature at which the reference data is defined.

chemicalPotential(temperature=None)

Calculate the chemical potential.

Returns:

The chemical potential of the atom calculated from the internal energy and entropy per atom of the specified element in some reference configuration.

Return type:

PhysicalQuantity of type energy | None

electronicInternalEnergy()
Returns:

The internal energy component of the atomic chemical potential.

Return type:

PhysicalQuantity of type energy

element()
Returns:

The element for which the atomic chemical potential is defined.

Return type:

PeriodicTableElement

entropy(temperature=None)
Returns:

The internal energy component of the atomic chemical potential.

Return type:

PhysicalQuantity of type energy per temperature

referenceTemperature()
Returns:

The reference temperature for the chemical potential.

Return type:

PhysicalQuantity of type temperature.

uniqueString()

Return a unique string representing the state of the object.

vibrationalInternalEnergy(temperature=None)
Returns:

The vibrational part of the internal energy. In this reference it is defined as 0 eV, as vibrational energy is included in the specified internal energy.

Return type:

PhysicalQuantity of type energy

Notes

The ReferenceChemicalPotential object defines an atomic chemical potential used in a ChargedPointDefectConfiguration calculation. The ReferenceChemicalPotential provides the reservoir energy for the element being added or removed from the pristine material to form the defect. This energy is used in calculating the formation energy and concentration of the defect. The value of the reservoir energy can depend on the nature of the environment around the defect. The atomic chemical potential also depends on the reference calculator used in the calculation, as it also includes the energy of the isolated atom according to this calculator.

The ReferenceChemicalPotential object is created by specifying the element for the potential. Optionally the internal energy of the atom is given using the internal_energy argument. The atomic entropy, which is usually derived from the vibrational entropy in the reference state, can also be given with the entropy argument. If the entropy is given, the total value of the chemical potential is temperature dependent.