OPTICS_XC_FUNCTIONAL (.param)

Keyword type

String

Description

This keyword controls which functional is used to calculate the exchange-correlation potential during an optics run. This option allows you to apply screened and exact exchange functionals non-self-consistently to obtain more accurate band gaps than with LDA or GGA functionals. Available options are:

• LDA - Local Density Approximation
• PW91 - Perdew Wang '91 GGA
• PBE - Perdew Burke Ernzerhof
• RPBE - Revised Perdew Burke Ernzerhof
• WC - Wu-Cohen
• PBESOL - PBEsol, PBE functional for solids
• HF - exact exchange, no correlation
• HF-LDA - exact exchange, LDA correlation
• sX - screened exchange, no correlation
• sX-LDA - screened exchange, LDA correlation
• PBE0 - PBE0 hybrid functional
• B3LYP - B3LYP hybrid functional
• HSE03 - HSE03 hybrid functional
• HSE06 - HSE06 hybrid functional
• RSCAN - regularized SCAN meta-GGA functional

Default

The default value is derived from the value for XC_FUNCTIONAL.

Example

OPTICS_XC_FUNCTIONAL : PW91

See Also:

XC_FUNCTIONAL
CASTEP keyword glossary
CASTEP parameters keywords