CASTEP > Dialogs in CASTEP > CASTEP Calculation dialog > Electronic tab > CASTEP Electronic Options dialog > DFT-D tab

DFT-D tab

The DFT-D tab allows you to set up customized parameters for van der Waals dispersion corrections. This can involve the definition of DFT-D corrections for exchange functionals that are not usually supported, the definition of support for additional elements, or changing existing parameters.

Use custom DFT-D parameters: Specify whether to use custom DFT-D parameters. When this checkbox is checked, select the van der Waals scheme to use from the dropdown list, options are:

The option selected will automatically update the Use method for DFT-D correction setting on the Setup tab of the CASTEP Calculation dialog.

Atomic parameters

This table allows you to edit the dispersion correction parameters for each of the atomic species. The type and number of parameters depend on the DFT-D scheme selected, please refer to the original literature for the meaning and usage of each parameter.

The units for all parameters are in eV for energies and in Å for lengths. The available columns are:

Element: Denotes the element to be edited.

C6 (eV Å6): Available for TS and Grimme schemes.

R0 (Å): Available for TS and Grimme schemes.

alpha (Å3): Available for TS and OBS schemes.

I (eV): Available for the OBS scheme.

Rvdw (Å): Available for the OBS scheme.

Only the elements in the currently active document are listed in the Atomic parameters table .

Each scheme includes a radius (R0 for TS and Grimme, Rvdw for OBS) that must be non-zero for each of the active elements.

Scheme parameters

Scheme parameters are dimensionless numbers that define the functional form of each scheme.

Please refer to the original literature to for the meaning and usage of each parameter.

Depending on the van der Waals scheme selected for the custom DFT-D parameters setting, the Scheme parameters that can be specified are: 

The default values for these parameters depend on the exchange correlation functional selected on the Setup tab of the CASTEP Calculation dialog.

Both scheme parameters must be non-zero for the calculations to start and for input files to be written.

Reset All: Restores the default settings for each element in the grid.

Access methods

Menu Modules | CASTEP | Calculation | Electronic | More... | DFT-D
Toolbar CASTEP | Calculation | Electronic | More... | DFT-D
See Also:

Pseudopotentials
Setting electronic options
Electronic tab - CASTEP Calculation dialog
Basis tab - CASTEP Electronic Options dialog
SCF tab - CASTEP Electronic Options dialog
k-points tab - CASTEP Electronic Options dialog
Potentials tab - CASTEP Electronic Options dialog
CASTEP Real Space Potentials dialog

Accelrys Materials Studio 8.0 Help: Wednesday, December 17, 2014
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