DFT Section

The DFT section requests a Kohn–Sham DFT calculation and selects the exchange–correlation functional and numerical grid. If no SCF Algorithm is provided, DFT defaults to a restricted reference for singlets and uses the molecule multiplicity to dispatch open-shell calculations.

Keywords

KeywordAliasesTypeDescription
FunctionalXC, Exchange, Correlation, Methodfunctional nameSelects the DFT functional
GridGridType, Grid_Typepreset or RRRAAASelects the atom-centered XC grid

Lines without a key are also accepted, so PBE0 and UltraFine inside the section are equivalent to Functional PBE0 and Grid UltraFine.

Functional names

FunctionalAccepted namesNotes
BP86BP86, B88P86pure GGA
PBEPBE, PBEPBEpure GGA
TPSSTPSSpure meta-GGA
M06-LM06L, M06-Lpure meta-GGA
B3LYPB3LYPhybrid GGA, 20% exact exchange
PBE0PBE0, PBE1PBEhybrid GGA, 25% exact exchange
M06-2XM062X, M06-2Xhybrid meta-GGA, 54% exact exchange
ωB97X-DWB97XD, W97XD, OmegaB97XD, ωB97X-Drange-separated hybrid with D2 dispersion

Function names are case-insensitive; hyphens, underscores, and parentheses are ignored during parsing.

Grid names

GridMeaning
Coarse, CoarseGrid, Pass0GridSmall smoke-test grid
SG1, SG1GridSG1-style route alias; maps through integral grid options
Medium, MediumGridMedium DFT grid
Fine, FineGridFine DFT grid
UltraFine, UltraFineGridLarger production grid
SuperFine, SuperFineGridLargest built-in preset
RRRAAACustom radial/angular count, e.g. 099302 = 99 radial × 302 angular

Custom grid values are six digits: first three digits are radial points, last three are the requested angular order. Requested angular orders up to 302 use genuine Lebedev–Laikov grids where available; requests above 302 use the Fibonacci-sphere fallback.

Examples

PBE0 with UltraFine grid:

title: Water PBE0 DFT

MOLECULE
  Charge 0
  Multiplicity 1
  Units Angstrom
END

task: STO-3G

DFT
  Functional PBE0
  Grid UltraFine
END

SCF
  MaxCycle 100
  Conver 8
END

GEOMETRY
O 0.000000  0.000000  0.117000
H 0.000000  0.755000 -0.471000
H 0.000000 -0.755000 -0.471000
END

M06-L with a custom 99 × 302 grid:

title: H2 M06-L custom grid

task: STO-3G

DFT
  M06-L
  Grid 099302
END

SCF
  MaxCycle 80
  Conver 8
END

GEOMETRY
H 0.000000 0.000000 0.000000
H 0.000000 0.000000 0.740000
END

Notes

  • DFT calculations still use the SCF section for convergence controls such as MaxCycle, Conver, Direct, checkpointing, and damping.
  • Exact exchange in hybrid and range-separated functionals increases cost because exchange matrix builds require electron-repulsion integrals.
  • Meta-GGA functionals (TPSS, M06-L, M06-2X) require kinetic-energy density on the grid and are more sensitive to grid quality than GGAs.