Optical properties selection

The following options are available when Optical properties is selected from the list of properties.

Results file: Select the CASTEP results file from which the optical properties information will be taken. When more than one set of results is available, use the button to browse the current directory and appropriate subdirectories for results files.

Calculation: Specify the type of optical properties calculation to be performed. Available options are:

Polarized - optical properties are calculated for plane polarized light with the specified polarization direction.
Unpolarized - optical properties are averaged over polarization directions perpendicular to the specified incident direction.
Polycrystalline - optical properties are averaged over all polarization directions, thereby imitating an experiment on a polycrystalline sample.

Smearing: Specify the Gaussian broadening to be used for calculating the dielectric function.

Scissors: Specify the scissors operator to be used for calculating the dielectric function.

The scissors operator is only applied for insulating systems, which have a clear separation between valence band and conduction band states. It is ignored for metallic systems.

Polarization: Specify the polarization of the incident radiation for the optical properties calculation. The direction is specified in fractional (lattice) coordinates.

This option is enabled only if a Polarized calculation is selected.

Incidence: Specify the incident direction of radiation the for optical properties calculation. The direction is specified in fractional (lattice) coordinates.

This option is enabled only if an Unpolarized calculation is selected.

Function: Specify which optical property should be displayed as a function of frequency when the View button is pressed. Available options are:

Reflectivity
Absorption
Refractive Index - both the real part, n, and imaginary part, k, of the complex optical constant are displayed.
Dielectric Function - both the real and imaginary parts are displayed.
Conductivity - both the real and imaginary parts are displayed.
Loss Function

Units: Specify the frequency units used for the display of optical properties.

More...: Provides access to the Optics Analysis Options dialog, which allows you to specify any Drude contribution to the optical properties.

Calculate: Calculates the dielectric function from the optical matrix elements and eigenvalues in the CASTEP results file.

A grid document is produced containing the calculated dielectric function.

View: Displays the selected optical property as a function of frequency.

This button is enabled only if the current document is a grid document containing a dielectric function.

A chart document is created using the dielectric function information contained in the active grid document.

Access methods

Menu	Modules \| CASTEP \| Analysis \| Optical properties
Toolbar	\| Analysis \| Optical properties

Optical properties selection

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