CASTEP > Dialogs in CASTEP > CASTEP Calculation dialog > Electronic tab > CASTEP Electronic Options dialog > SCF tab > CASTEP Occupancy Options dialog

The CASTEP Occupancy Options dialog provides access to parameters that control occupancies in CASTEP calculations.

By default, CASTEP calculations are performed with variable occupancy. The fixed occupancy option is only suitable for structures that are known to be insulators or closed shell systems at the level of theory used in the CASTEP calculation.

Empty bands: Specify the number of additional bands to be included in an electronic minimization as a percentage of the number of occupied bands.

This option is enabled only for variable occupancy calculations.

Smearing: Specify the broadening to be applied to the electronic occupation.

This option is enabled only for variable occupancy calculations.

Optimize total spin after: Specify the number of SCF iterations for which the total electronic spin will remain fixed before being allowed to vary.

This option is enabled only for spin-polarized variable occupancy calculations.

The spin will be fixed throughout the calculation (including possible steps of geometry optimization) if the checkbox is unchecked.

In spin-polarized systems there may be more than one stable SCF solution with different total spin values. By setting the initial spin on the Setup tab and by fixing the total spin value for a number of SCF iterations, it is possible to exert some control over which solution is found.

Help: Displays

Access methods

Menu | Modules | CASTEP | Calculation | Electronic | More... | SCF | More... |

Toolbar | | Calculation | Electronic | More... | SCF | More... |

Setting up SCF parameters

Electronic tab - CASTEP Calculation dialog

SCF tab - CASTEP Electronic Options dialog

Self-consistent electronic minimization

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