FNOCC

General

ACTIVE_NAT_ORBS

An array containing the number of virtual natural orbitals per irrep (in Cotton order) so a user can specify the number of retained natural orbitals rather than determining them with OCC_TOLERANCE This keyword overrides OCC_TOLERANCE and OCC_PERCENTAGE

  • Type: array

  • Default: No Default

BRUECKNER_MAXITER

Maximum number of iterations for Brueckner orbitals optimization

  • Type: integer

  • Default: 20

CC_SCALE_OS

Oppposite-spin scaling factor for SCS-CCSD

  • Type: double

  • Default: 1.27

CC_SCALE_SS

Same-spin scaling factor for SCS-CCSD

  • Type: double

  • Default: 1.13

CC_TIMINGS

Do time each cc diagram?

CEPA_NO_SINGLES

Flag to exclude singly excited configurations from a coupled-pair computation.

CHOLESKY_TOLERANCE

tolerance for Cholesky decomposition of the ERI tensor

DFCC

Do use density fitting or cholesky decomposition in CC? This keyword is used internally by the driver. Changing its value will have no effect on the computation.

DF_BASIS_CC

Auxilliary basis for df-ccsd(t).

  • Type: string

  • Possible Values: basis string

  • Default: No Default

DIIS_MAX_VECS

Desired number of DIIS vectors

  • Type: integer

  • Default: 8

DIPMOM

Compute the dipole moment? Note that dipole moments are only available in the FNOCC module for the ACPF, AQCC, CISD, and CEPA(0) methods.

E_CONVERGENCE

Convergence criterion for CC energy. See Table Post-SCF Convergence for default convergence criteria for different calculation types. Note that convergence is met only when E_CONVERGENCE and R_CONVERGENCE are satisfied.

MAXITER

Maximum number of CC iterations

  • Type: integer

  • Default: 100

MP2_SCALE_OS

Opposite-spin scaling factor for SCS-MP2

  • Type: double

  • Default: 1.20

MP2_SCALE_SS

Same-spin scaling factor for SCS-MP2

  • Type: double

  • Default: 1.0

NAT_ORBS

Do use MP2 NOs to truncate virtual space for QCISD/CCSD and (T)?

OCC_PERCENTAGE

Cutoff for occupation of MP2 virtual NOs in FNO-QCISD/CCSD(T). The number of virtual NOs is chosen so the occupation of the truncated virtual space is OCC_PERCENTAGE percent of occupation of the original MP2 virtual space. This option is only used if NAT_ORBS = true. This keyword overrides OCC_TOLERANCE

  • Type: double

  • Default: 99.0

OCC_TOLERANCE

Cutoff for occupation of MP2 virtual NOs in FNO-QCISD/CCSD(T). Virtual NOs with occupations less than OCC_TOLERANCE will be discarded. This option is only used if NAT_ORBS = true.

R_CONVERGENCE

Convergence for the CC amplitudes. Note that convergence is met only when E_CONVERGENCE and R_CONVERGENCE are satisfied.

SCS_CCSD

Do SCS-CCSD?

SCS_CEPA

Do SCS-CEPA? Note that the scaling factors will be identical to those for SCS-CCSD.

SCS_MP2

Do SCS-MP2?

TRIPLES_LOW_MEMORY

Do use low memory option for triples contribution? Note that this option is enabled automatically if the memory requirements of the conventional algorithm would exceed the available resources. The low memory algorithm is faster in general and has been turned on by default starting September 2020.

Expert

CEPA_LEVEL

Which coupled-pair method is called? This parameter is used internally by the python driver. Changing its value won’t have any effect on the procedure.

  • Type: string

  • Default: CEPA(0)

COMPUTE_MP4_TRIPLES

Do compute MP4 triples contribution?

COMPUTE_TRIPLES

Do compute triples contribution?

RUN_CCSD

do ccsd rather than qcisd?

RUN_CEPA

Is this a CEPA job? This parameter is used internally by the pythond driver. Changing its value won’t have any effect on the procedure.

RUN_MP2

do only evaluate mp2 energy?

RUN_MP3

do only evaluate mp3 energy?

RUN_MP4

do only evaluate mp4 energy?

USE_DF_INTS

Use 3-index integrals to generate 4-index ERI’s? This keyword is used for testing purposes only. Changing its value will have no effect on the computation.