SAPT

Performs symmetry adapted perturbation theory (SAPT) analysis to quantitatively analyze non-covalent interactions.

SAPT(HF)

AIO_CPHF

Do use asynchronous disk I/O in the solution of the CPHF equations? Use may speed up the computation slightly at the cost of spawning an additional thread.

AIO_DF_INTS

Do use asynchronous disk I/O in the formation of the DF integrals? Use may speed up the computation slightly at the cost of spawning an additional thread.

BASIS

Primary basis set, describes the monomer molecular orbitals

  • Type: string

  • Possible Values: basis string

  • Default: No Default

CCD_E_CONVERGENCE

E converge value for CCD

CCD_MAXITER

Max CCD iterations

  • Type: integer

  • Default: 50

CCD_T_CONVERGENCE

Convergence tolerance for CCD amplitudes

CPHF_R_CONVERGENCE

Convergence criterion for residual of the CPHF/CPKS coefficients in the SAPT \(E_{ind,resp}^{(20)}\) term. This applies to wavefunction-based SAPT or SAPT(DFT). See CPHF_R_CONVERGENCE for fragment-partitioned or intramolecular SAPT.

DENOMINATOR_ALGORITHM

Denominator algorithm for PT methods. Laplace transformations are slightly more efficient.

  • Type: string

  • Possible Values: LAPLACE, CHOLESKY

  • Default: LAPLACE

DENOMINATOR_DELTA

Maximum error allowed (Max error norm in Delta tensor) in the approximate energy denominators employed for most of the \(E_{disp}^{(20)}\) and \(E_{exch-disp}^{(20)}\) evaluation.

  • Type: double

  • Default: 1.0e-6

DF_BASIS_ELST

Auxiliary basis set for SAPT Elst10 and Exch10 density fitting computations, may be important if heavier elements are involved. Defaults to a JKFIT basis. Previous to v1.6, defaulted to DF_BASIS_SAPT See fitting notes .

  • Type: string

  • Possible Values: basis string

  • Default: No Default

DF_BASIS_SAPT

Auxiliary basis set for SAPT density fitting computations. Defaults to a RI basis.

  • Type: string

  • Possible Values: basis string

  • Default: No Default

EXCH_SCALE_ALPHA

Whether or not to perform exchange scaling for SAPT exchange components. Default is false, i.e. no scaling. If set to true, performs scaling with \(Exch10 / Exch10(S^2)\). If set to a value \(\alpha\), performs scaling with \((Exch10 / Exch10(S^2))^{\alpha}\).

  • Type: string

  • Default: FALSE

FREEZE_CORE

The scope of core orbitals to freeze in evaluation of SAPT \(E_{disp}^{(20)}\) and \(E_{exch-disp}^{(20)}\) terms. Recommended true for all SAPT computations

  • Type: string

  • Possible Values: FALSE, TRUE

  • Default: FALSE

INTS_TOLERANCE

Schwarz screening threshold. Minimum absolute value below which all three-index DF integrals and those contributing to four-index integrals are neglected. The default is conservative, but there isn’t much to be gained from loosening it, especially for higher-order SAPT.

MAXITER

Maximum number of CPHF iterations

  • Type: integer

  • Default: 50

MAX_CCD_DIISVECS

Maximum number of vectors used in CCD-DIIS

  • Type: integer

  • Default: 10

MIN_CCD_DIISVECS

Minimum number of vectors used in CCD-DIIS

  • Type: integer

  • Default: 4

NAT_ORBS_T2

Do use MP2 natural orbital approximations for the \(v^4\) block of two-electron integrals in the evaluation of second-order T2 amplitudes? Recommended true for all SAPT computations.

NAT_ORBS_T3

Do natural orbitals to speed up evaluation of the triples contribution to dispersion by truncating the virtual orbital space? Recommended true for all SAPT computations.

NAT_ORBS_V4

Do use MP2 natural orbital approximations for the \(v^4\) block of two-electron integrals in the evaluation of CCD T2 amplitudes? Recommended true for all SAPT computations.

OCC_TOLERANCE

Minimum occupation (eigenvalues of the MP2 OPDM) below which virtual natural orbitals are discarded for in each of the above three truncations

PRINT

The amount of information to print to the output file for the sapt module. For 0, only the header and final results are printed. For 1, (recommended for large calculations) some intermediate quantities are also printed.

  • Type: integer

  • Default: 1

SAPT_LEVEL

The level of theory for SAPT

  • Type: string

  • Possible Values: SAPT0, SAPT2, SAPT2+, SAPT2+3

  • Default: SAPT0

SAPT_MEM_CHECK

Do force SAPT2 and higher to die if it thinks there isn’t enough memory? Turning this off is ill-advised.

SAPT_MEM_SAFETY

Memory safety

  • Type: double

  • Default: 0.9

SAPT(DFT)

SAPT_DFT_DO_DHF

Compute the Delta-HF correction?

SAPT_DFT_EXCH_DISP_SCALE_SCHEME

Scheme for approximating exchange-dispersion for SAPT-DFT. Previous to Nov 2022, default was FIXED with Hesselmann value. NONE Use unscaled Exch-Disp2,u . FIXED Use a fixed factor SAPT_DFT_EXCH_DISP_FIXED_SCALE to scale Exch-Disp2,u . DISP Use the ratio of Disp2,r and Disp2,u to scale Exch-Disp2,u .

  • Type: string

  • Possible Values: NONE, FIXED, DISP

  • Default: FIXED

SAPT_DFT_GRAC_SHIFT_A

Monomer A GRAC shift in Hartree

  • Type: double

  • Default: 0.0

SAPT_DFT_GRAC_SHIFT_B

Monomer B GRAC shift in Hartree

  • Type: double

  • Default: 0.0

Expert SAPT(HF)

COUPLED_INDUCTION

Solve the CPHF equations to compute coupled induction and exchange-induction. These are not available for ROHF, and the option is automatically false in this case. In all other cases, coupled induction is strongly recommended. Only turn it off if the induction energy is not going to be used.

DO_CCD_DISP

Do CCD dispersion correction in SAPT2+, SAPT2+(3) or SAPT2+3?

DO_DISP_EXCH_SINF

For SAPT0 or SAPT(DFT), compute the non-approximated second-order exchange-dispersion term.

DO_IND30_EXCH_SINF

For SAPT2+3, compute the non-approximated third-order exchange-induction term.

DO_IND_EXCH_SINF

For SAPT0 or SAPT(DFT), compute the non-approximated second-order exchange-induction term.

DO_MBPT_DISP

Do MBPT dispersion correction in SAPT2+, SAPT2+(3) or SAPT2+3, if also doing CCD?

DO_THIRD_ORDER

Do compute third-order corrections?

SAPT0_E10

For SAPT0 only, compute only first-order electrostatics and exchange. The integrals are computed before any terms, so all integrals will be computed even if they are not needed for the requested term

SAPT0_E20DISP

For SAPT0 only, compute only second-order induction The integrals are computed before any terms, so all integrals will be computed even if they are not needed for the requested term

SAPT0_E20IND

For SAPT0 only, compute only second-order induction The integrals are computed before any terms, so all integrals will be computed even if they are not needed for the requested term

SAPT_MEM_FACTOR

Proportion of memory available for the DF-MP2 three-index integral buffers used to evaluate dispersion.

  • Type: double

  • Default: 0.9

Expert SAPT(DFT)

SAPT_DFT_DO_HYBRID

Enables the hybrid xc kernel in dispersion?

SAPT_DFT_EXCH_DISP_FIXED_SCALE

Exch-disp scaling factor for FIXED scheme for SAPT_DFT_EXCH_DISP_SCALE_SCHEME Default value of 0.770 suggested in Y. Xie, D. G. A. Smith and C. D. Sherrill, 2022 (submitted). Previous to Nov 2022, default value was 0.686 suggested by Hesselmann and Korona, J. Chem. Phys. 141, 094107 (2014).

  • Type: double

  • Default: 0.770

SAPT_DFT_FUNCTIONAL

Underlying funcitonal to use for SAPT(DFT)

  • Type: string

  • Default: PBE0

SAPT_DFT_GRAC_DETERMINATION

How is the GRAC correction determined?

  • Type: string

  • Possible Values: INPUT

  • Default: INPUT

SAPT_DFT_MP2_DISP_ALG

Which MP2 Exch-Disp module to use?

  • Type: string

  • Possible Values: FISAPT, SAPT

  • Default: SAPT

SAPT_FDDS_DISP_LEG_LAMBDA

Lambda shift in the space morphing for the FDDS Dispersion time integration

  • Type: double

  • Default: 0.3

SAPT_FDDS_DISP_NUM_POINTS

Number of points in the Legendre FDDS Dispersion time integration

  • Type: integer

  • Default: 10

SAPT_FDDS_V2_RHO_CUTOFF

Minimum rho cutoff for the in the LDA response for FDDS

  • Type: double

  • Default: 1.e-6

SAPT_QUIET

Interior option to clean up printing