SAPT

Performs symmetry adapted perturbation theory (SAPT) analysis to quantitatively analyze noncovalent interactions.

General

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.

• Type: boolean
• Default: false

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.

• Type: boolean
• Default: false

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

• Type: conv double
• Default: 1e-8

CCD_MAXITER

Max CCD iterations

• Type: integer
• Default: 50

CCD_T_CONVERGENCE

Convergence tolerance for CCD amplitudes

• Type: conv double
• Default: 1e-8

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 and 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 DF_BASIS_SAPT

• 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

D_CONVERGENCE

Convergence criterion for residual of the CPHF coefficients in the SAPT term.

• Type: conv double
• Default: 1e-8

E_CONVERGENCE

Convergence criterion for energy (change) in the SAPT term during solution of the CPHF equations.

• Type: conv double
• Default: 1e-10

FREEZE_CORE

The scope of core orbitals to freeze in evaluation of SAPT and terms. Recommended true for all SAPT computations

• Type: string
• Possible Values: FALSE, TRUE
• Default: FALSE

INTS_TOLERANCE

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.

• Type: conv double
• Default: 1.0e-12

MAXITER

Maxmum 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

Minimumnumber of vectors used in CCD-DIIS

• Type: integer
• Default: 4

NAT_ORBS

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.

• Type: boolean
• Default: false

NAT_ORBS_T2

Do use MP2 natural orbital approximations for the block of two-electron integrals in the evaluation of second-order T2 amplitudes? This approximation is promising for accuracy and computational savings, but it has not been rigorously tested.

• Type: boolean
• Default: false

NO_RESPONSE

Don’t solve the CPHF equations? Evaluate and instead of their response-including coupterparts. Only turn on this option if the induction energy is not going to be used.

• Type: boolean
• Default: false

OCC_TOLERANCE

Minimum occupation (eigenvalues of the MP2 OPDM) below which virtual natural orbitals are discarded for evaluating the triples contribution to dispersion.

• Type: conv double
• Default: 1.0e-6

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.

• Type: boolean
• Default: true

SAPT_MEM_SAFETY

Memory safety

• Type: double
• Default: 0.9

SAPT_OS_SCALE

The scale factor used for opposite-spin pairs in SCS computations. SS/OS decomposition performed for and terms.

• Type: double
• Default: 6.0/5.0

SAPT_SS_SCALE

The scale factor used for same-spin pairs in SCS computations. SS/OS decomposition performed for and terms.

• Type: double
• Default: 1.0/3.0

Expert

DO_CCD_DISP

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

• Type: boolean
• Default: false

DO_THIRD_ORDER

Do compute third-order corrections?

• Type: boolean
• Default: false