5.3 Overview of Available Functionals

5.3.5 Specialized Functionals

  • SRC1-R1: TDDFT short-range corrected functional [Eq. (1) in Ref. 93, 1st row atoms]

  • SRC1-R2: TDDFT short-range corrected functional [Eq. (1) in Ref. 93, 2nd row atoms]

  • SRC2-R1: TDDFT short-range corrected functional [Eq. (2) in Ref. 93, 1st row atoms]

  • SRC2-R2: TDDFT short-range corrected functional [Eq. (2) in Ref. 93, 2nd row atoms]

  • BR89: Becke-Roussel meta-GGA exchange functional modeled after the hydrogen atom63

  • B94: meta-GGA correlation functional by Becke that uses the BR89 exchange functional to compute the Coulomb potential69

  • B94hyb: modified version of the B94 correlation functional for use with the BR89B94hyb exchange-correlation functional69

  • BR89B94h: 15.4% HF exchange + 84.6% BR89 meta-GGA exchange + BR89hyb meta-GGA correlation69

  • BRSC: Exchange component of the original B05 exchange-correlation functional61

  • MB05: Exchange component of the modified B05 (BM05) exchange-correlation functional751

  • B05: A full exact-exchange Kohn-Sham scheme of Becke that uses the exact-exchange energy density (RI) and accounts for static correlation61, 754, 753

  • BM05 (XC): Modified B05 hyper-GGA scheme that uses MB05 instead of BRSC as the exchange functional751

  • PSTS: Hyper-GGA (100% HF exchange) exchange-correlation functional of Perdew, Staroverov, Tao, and Scuseria708

  • MCY2: Mori-Sánchez-Cohen-Yang adiabatic connection-based hyper-GGA exchange-correlation functional644, 181, 576

This example illustrate the use of the RI-B05 and RI-PSTS functionals. These are presently available only for single-point calculations, and convergence is greatly facilitated by obtaining converged SCF orbitals from, e.g., an LDA or HF calculation first. (LDA is used in the example below but HF can be substituted.) Use of the RI approximation (Section 6.6) requires specification of an auxiliary basis set.

Example 5.1  Q-Chem input of H2 using RI-B05.

$comment
   H2, example of SP RI-B05.  First do a well-converged LSD, G3LARGE is the
   basis of choice for good accuracy. The input lines
   PURECART    2222
   SCF_GUESS   CORE
   are obligatory for the time being here.
$end

$molecule
0 1
H   0.  0.   0.0
H   0.  0.   0.7414
$end

$rem
   SCF_GUESS        core
   METHOD           lda
   BASIS            g3large
   PURECART         2222
   THRESH           14
   INCDFT           false
   SYM_IGNORE       true
   SYMMETRY         false
   SCF_CONVERGENCE  9
$end

@@@

$comment
   For the time being the following input lines are obligatory:
   PURECART        2222
   AUX_BASIS       riB05-cc-pvtz
   DFT_CUTOFFS     0
   MAX_SCF_CYCLES  0
$end

$molecule
   read
$end

$rem
   SCF_GUESS       read
   EXCHANGE        b05   ! or set to psts for ri-psts
   PURECART        2222
   BASIS           g3large
   AUX_BASIS       rib05-cc-pvtz  ! the aux basis for both RI-B05 and RI-PSTS
   THRESH          4
   PRINT_INPUT     true
   INCDFT          false
   SYM_IGNORE      true
   SYMMETRY        false
   MAX_SCF_CYCLES  0
   DFT_CUTOFFS     0
$end