ElectronDensity

	ElectronDensity
ElectronDifferenceDensity	ElectrostaticDifferencePotential

Name

ElectronDensity — Class for calculating the electron density

Synopsis

Namespace: NanoLanguage

ElectronDensity(
configuration,
spin
)

Description

A class for calculating the electron density for a configuration.

ElectronDensity Arguments

configuration

The configuration for which the density should be calculated.

Type: MoleculeConfiguration | BulkConfiguration | DeviceConfiguration

spin

The spin for which the density should be calculated.

Type: Spin.Sum | Spin.Up | Spin.Down

Default:


          Spin.Sum

ElectronDensity Methods

A ElectronDensity object provides the following methods:

derivatives(x, y, z): Calculate the derivative in the point x,y,z.

x

The cartesian x coordinate.

Type: physical quantity with type length.

y

The cartesian y coordinate.

Type: physical quantity with type length.

z

The cartesian z coordinate.

Type: physical quantity with type length.
evaluate(x, y, z): Evaluate in the point x,y,z

x

The cartesian x coordinate.

Type: physical quantity with type length.

y

The cartesian y coordinate.

Type: physical quantity with type length.

z

The cartesian z coordinate.

Type: physical quantity with type length.
gridCoordinate(i, j, k): Return the coordinate for a given grid index.

i

The grid index in the A direction.

Type: integer

j

The grid index in the B direction.

Type: integer

k

The grid index in the C direction.

Type: integer
nlprint(stream): Method for printing an ASCII table with the electron density.

stream

The stream the electron density should be written to.
Type: A stream that supports strings being written to using 'write'.
Default: sys.stdout
scale(scale): Scale the field with a double.

scale

The parameter to scale with.

Type: float
shape(): Query function for getting the shape of the data.
spin(): Query method for getting 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.

Usage Examples

Calculate the electron density and save it to a file

# Set up configuration
molecule_configuration = MoleculeConfiguration(
    elements=[Nitrogen, Hydrogen, Hydrogen, Hydrogen],
    cartesian_coordinates=[[ 0.     ,  0.      ,  0.124001],
                           [ 0.     ,  0.941173, -0.289336],
                           [ 0.81508, -0.470587, -0.289336],
                           [-0.81508, -0.470587, -0.289336]]*Angstrom 
    )

# Define the calculator
calculator = LCAOCalculator()
molecule_configuration.setCalculator(calculator)

# Calculate and save the electron density
electron_density = ElectronDensity(molecule_configuration)
nlsave('results.nc', electron_density)

nh3_electron_density.py

For examples on how to average and handle 3-d grids, see the examples for ElectronDifferenceDensity and ElectrostaticDifferencePotential.

Notes

ElectronDensity, returns the valence electron density.
To export the grid data of an electron density, use the method nlprint.
Calculation of the electron density is not supported for the HuckelCalculator.


ElectronDifferenceDensity		ElectrostaticDifferencePotential