Section EXCHANGE

• Setup parameters for the evaluation of the EXCHANGE and core Hamiltonian terms in SE calculations.

• Section path: CP2K_INPUT / FORCE_EVAL / DFT / QS / SE / EXCHANGE

• This section cannot be repeated and can be optional.

• Subsections

  • none

• Keywords

  • CUTOFF
  • RC_RANGE
  • RC_TAPER

• Keyword descriptions

  CUTOFF
  	CUTOFF {REAL}
  	Atomic Cutoff Radius Cutoff for the evaluation of the Exchange integrals. For non-periodic calculation the default value is exactly the full cell dimension, in order to evaluate all pair interactions. Instead, for periodic calculations the default is the minimum value between 1/4 of the cell dimension and the value specified in input (either explicitly defined or the default numerical value).
  	This optional keyword cannot be repeated and it expects precisely one real.
  	Default value: 1.20000000E+01
  	Default unit: [angstrom]

  RC_RANGE
  	RC_RANGE {REAL}
  	Range of cutoff switch function (tapering): 0.5*(1-TANH((r-r0)/RC_RANGE)), where r0=2.0*RC_TAPER-20.0*RC_RANGE.
  	This optional keyword cannot be repeated and it expects precisely one real.
  	Default value: 0.00000000E+00
  	Default unit: [angstrom]

  RC_TAPER
  	RC_TAPER {REAL}
  	Atomic Cutoff Radius Cutoff for Tapering Exchange integrals. If not specified it assumes the same value specified for the CUTOFF.
  	This optional keyword cannot be repeated and it expects precisely one real.
  	Default unit: [angstrom]