5.3 Overview of Available Functionals

5.3.1 Suggested Density Functionals

(May 16, 2021)

Q-Chem contains over 150 exchange-correlation functionals, not counting those that can be straightforwardly appended with a dispersion correction (such as B3LYP-D3). Therefore, we suggest a few functionals from the second through fourth rungs of Jacob’s Ladder in order to guide functional selection. Most of these suggestions come from a benchmark of over 200 density functionals on a vast database of nearly 5000 data points, covering non-covalent interactions, isomerization energies, thermochemistry, and barrier heights. The single recommended method from each category is indicated in bold.

From the GGAs on Rung 2, we recommend:

  • B97-D3(BJ): METHOD = B97-D3 and DFT_D = D3_BJ

  • revPBE-D3(BJ): METHOD = revPBE and DFT_D = D3_BJ

  • BLYP-D3(BJ): METHOD = BLYP and DFT_D = D3_BJ

  • PBE: METHOD = PBE

From the meta-GGAs on Rung 3, we recommend:

  • B97M-rV: METHOD = B97M-rV

  • MS1-D3(0): METHOD = MGGA_MS1 and DFT_D = D3_ZERO

  • MS2-D3(0): METHOD = MGGA_MS2 and DFT_D = D3_ZERO

  • M06-L-D3(0): METHOD = M06-L and DFT_D = D3_ZERO

  • TPSS-D3(BJ): METHOD = TPSS and DFT_D = D3_BJ

From the hybrid GGAs on Rung 4, we recommend:

  • ωB97X-V: METHOD = wB97X-V

  • ωB97X-D3: METHOD = wB97X-D3

  • ωB97X-D: METHOD = wB97X-D

  • B3LYP-D3(BJ): METHOD = B3LYP and DFT_D = D3_BJ

  • revPBE0-D3(BJ): METHOD = revPBE0 and DFT_D = D3_BJ

From the hybrid meta-GGAs on Rung 4, we recommend:

  • ωB97M-V: METHOD = wB97M-V

  • ωM05-D: METHOD = wM05-D

  • M06-2X-D3(0): METHOD = M06-2X and DFT_D = D3_ZERO

  • TPSSh-D3(BJ): METHOD = TPSSh and DFT_D = D3_BJ

From the double-hybrid GGAs on Rung 5, we recommend:

  • ωB97X-2(LP): METHOD = wB97X-2(LP)

  • ωB97X-2(TQZ): METHOD = wB97X-2(TQZ)

  • DSD-PBEPBE-D3: METHOD = DSD-PBEPBE-D3

From the double-hybrid mGGAs on Rung 5, we recommend:

  • ωB97M-(2): METHOD = wB97M-(2)

  • PTPSS-D3: METHOD = PTPSS-D3