 |
Eigenstate |  |
|---|---|---|
| Stress | BlochState |
A class for calculating the eigenstate of a particular orbital in a configuration.
The configuration for which the eigenstate should be calculated.
Type: MoleculeConfiguration | BulkConfiguration | DeviceConfiguration
The quantum number of the desired eigenstate.
Type: integer
Default:
0
Specifies the orbitals within the configuration to include in the calculation.
Type: ProjectionList.
Default:
All atoms included : ProjectionList(All)
The spin to calculate the eigenstate for.
Type: Spin.Up | Spin.Down
Default:
Spin.Up
A Eigenstate object provides the following methods:
derivatives(x, y, z): Calculate the derivative in the point x,y,z.
evaluate(x, y, z): Evaluate in the point x,y,z
gridCoordinate(i, j, k): Return the coordinate for a given grid index.
nlprint(stream): Print a string containing an ASCII table useful for plotting the eigenstate.
scale(scale): Scale the field with a double.
shape(): Query function for getting the shape of the data.
spin(): Query for the spin.
toArray(): Return the values of the grid as a numpy array slicing off any units.
unit(): Get the unit of the data in the grid.
unitCell(): Return the unit cell for the grid.
volumeElement(): Get the volume element of the grid.
Calculate and save the eigenstate for water molecule in a NetCDF file.
# Define elements
elements = [Oxygen, Hydrogen, Hydrogen]
# Define coordinates
cartesian_coordinates = [[ 0.0, 0.000000000000, 1.20198000e-01],
[ 0.0, 7.59572000e-01, -4.86714000e-01],
[ 0.0, -7.59606000e-01, -4.86721000e-01]]*Angstrom
# Set up configuration
molecule_configuration = MoleculeConfiguration(
elements=elements,
cartesian_coordinates=cartesian_coordinates
)
# define a a calculator
molecule_configuration.setCalculator(LCAOCalculator())
# calculate and save the eigenstate with quantum number 0
eigenstate = Eigenstate(molecule_configuration, 0)
nlsave('eigenstate.nc', eigenstate)
For examples on how to average and handle 3-d grids, see the examples for ElectronDifferenceDensity and ElectrostaticDifferencePotential.
Using a projection list means that only the part of the Hamiltonian involving the atoms in the projection list will be used in the diagonalization to find the eigenstates.
Notice that the Eigenstate method neglects interactions across the unit cell boundaries. This makes sense physically for a MoleculeConfiguration where the interactions are artifacts of the calculation. For the BulkConfiguration and DeviceConfiguration however, the interactions across cell boundaries represent something real, so care should be taken when interpreting the results. For BulkConfiguration see Bloch state for an alternative analysis object.
