LHFCALC: Difference between revisions
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If one does not specifically request a particular hybrid functional (see {{TAG|AEXX}}, {{TAG|ALDAX}}, {{TAG|ALDAC}}, {{TAG|AGGAX}}, {{TAG|AGGAC}}, {{TAG|AMGGAX}}, {{TAG|AMGGAC}}, and the [[list_of_hybrid_functionals|list_of_hybrid_functionals]]) VASP will default to the [[list_of_hybrid_functionals#PBE0|PBE0 hybrid functional]]. | If one does not specifically request a particular hybrid functional (see {{TAG|AEXX}}, {{TAG|ALDAX}}, {{TAG|ALDAC}}, {{TAG|AGGAX}}, {{TAG|AGGAC}}, {{TAG|AMGGAX}}, {{TAG|AMGGAC}}, and the [[list_of_hybrid_functionals|list_of_hybrid_functionals]]) VASP will default to the [[list_of_hybrid_functionals#PBE0|PBE0 hybrid functional]]. | ||
{{NB|tip|For the most reliable convergence, select a "direct optimization" algorithm for HF/DFT hybrid functonal type calculations, i.e., {{TAGO|ALGO|Damped}} ({{TAGO|IALGO|53}}) or {{TAGO|ALGO|All}} ({{TAGO|IALGO|58}}) in the {{FILE|INCAR}} file. You may also consider {{TAGO|ALGO|Normal}} which in combination with {{TAGO|LFOCKACE|TRUE}} (the default) can be a fast alternative. Do not use {{TAGO|ALGO|Fast}} which is not properly supported (note: no warning is printed).}} | |||
If the blocked-Davidson algorithm {{TAGO|ALGO|Normal}} is used, in many cases the Pulay mixer will be unable to determine the proper ground-state. We hence recommend to select the blocked-Davidson algorithm only in combination with straight mixing or a Kerker like mixing (see the [[density_mixing|section on mixing]]). The following combination have been successfully applied for small and medium sized systems | |||
{{TAG|LHFCALC}} = .TRUE. ; {{TAG|ALGO}} = Normal ; {{TAG|IMIX}} = 1 ; {{TAG|AMIX}} = a | {{TAG|LHFCALC}} = .TRUE. ; {{TAG|ALGO}} = Normal ; {{TAG|IMIX}} = 1 ; {{TAG|AMIX}} = a | ||
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{{TAG|LTHOMAS}}, | {{TAG|LTHOMAS}}, | ||
{{TAG|LRHFCALC}}, | {{TAG|LRHFCALC}}, | ||
{{TAG|LFOCKACE}}, | |||
[[list_of_hybrid_functionals|List of hybrid functionals]], | [[list_of_hybrid_functionals|List of hybrid functionals]], | ||
[[Hybrid_functionals:_formalism|Hybrid functionals: formalism]] | [[Hybrid_functionals:_formalism|Hybrid functionals: formalism]] | ||
Latest revision as of 07:22, 17 October 2025
LHFCALC = .TRUE. | .FALSE.
Default: LHFCALC = .FALSE.
Description: LHFCALC specifies whether a Hartree-Fock/DFT hybrid functional type calculation is performed.
If one does not specifically request a particular hybrid functional (see AEXX, ALDAX, ALDAC, AGGAX, AGGAC, AMGGAX, AMGGAC, and the list_of_hybrid_functionals) VASP will default to the PBE0 hybrid functional.
Tip: For the most reliable convergence, select a "direct optimization" algorithm for HF/DFT hybrid functonal type calculations, i.e., ALGO = Damped (IALGO = 53) or ALGO = All (IALGO = 58) in the INCAR file. You may also consider ALGO = Normal which in combination with LFOCKACE = TRUE (the default) can be a fast alternative. Do not use ALGO = Fast which is not properly supported (note: no warning is printed).
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If the blocked-Davidson algorithm ALGO = Normal is used, in many cases the Pulay mixer will be unable to determine the proper ground-state. We hence recommend to select the blocked-Davidson algorithm only in combination with straight mixing or a Kerker like mixing (see the section on mixing). The following combination have been successfully applied for small and medium sized systems
LHFCALC = .TRUE. ; ALGO = Normal ; IMIX = 1 ; AMIX = a
Decrease the parameter a until convergence is reached.
In most cases, however, it is recommended to use the "Damped" algorithm with suitably chosen timestep. The following setup for the electronic optimization works reliably in most cases:
LHFCALC = .TRUE. ; ALGO = Damped ; TIME = 0.5
If convergence is not obtained, it is recommended to reduce the timestep TIME.
Related tags and articles
AEXX, ALDAX, ALDAC, AGGAX, AGGAC, AMGGAX, AMGGAC, HFSCREEN, LTHOMAS, LRHFCALC, LFOCKACE, List of hybrid functionals, Hybrid functionals: formalism