CCENERGY¶

Performs local MP2 computations for RHF reference functions.

General¶

ABCD¶

Type of ABCD algorithm will be used

Type: string

Possible Values: NEW, OLD

Default: NEW

ANALYZE¶

Do analyze T2 amplitudes

Type: boolean

Default: false

BRUECKNER_ORBS_R_CONVERGENCE¶

Convergence criterion for Breuckner orbitals. The convergence is determined based on the largest $T_1$ amplitude. Default adjusts depending on E_CONVERGENCE

Type: conv double

Default: 1e-5

CACHELEVEL¶

Cacheing level for libdpd governing the storage of amplitudes, integrals, and intermediates in the CC procedure. A value of 0 retains no quantities in cache, while a level of 6 attempts to store all quantities in cache. For particularly large calculations, a value of 0 may help with certain types of memory problems. The default is 2, which means that all four-index quantites with up to two virtual-orbital indices (e.g., $\langle ij | ab \rangle>$ integrals) may be held in the cache.

Type: integer

Default: 2

CACHETYPE¶

Selects the priority type for maintaining the automatic memory cache used by the libdpd codes. A value of LOW selects a “low priority” scheme in which the deletion of items from the cache is based on pre-programmed priorities. A value of LRU selects a “least recently used” scheme in which the oldest item in the cache will be the first one deleted.

Type: string

Possible Values: LOW, LRU

Default: LOW

CC_NUM_THREADS¶

Number of threads

Type: integer

Default: 1

CC_OS_SCALE¶

Coupled-cluster opposite-spin scaling value

Type: double

Default: 1.27

CC_SS_SCALE¶

Coupled-cluster same-spin scaling value

Type: double

Default: 1.13

DF_BASIS_MP2¶

Auxiliary basis set for MP2 density fitting calculations

Type: string

Possible Values: basis string

Default: No Default

DF_LMP2¶

Do use density fitting? Turned on with specification of fitting basis.

Type: boolean

Default: true

DIAG_METHOD¶

Diagonalization method for the CI matrix

Type: string

Possible Values: DAVIDSON, FULL

Default: DAVIDSON

DIIS¶

Do use DIIS extrapolation to accelerate convergence?

Type: boolean

Default: true

DIIS_MAX_VECS¶

Maximum number of error vectors stored for DIIS extrapolation

Type: integer

Default: 5

DIIS_START_ITER¶

Iteration at which to start DIIS extrapolation

Type: integer

Default: 3

DISTANT_PAIR_CUTOFF¶

Distant pair cutoff

Type: double

Default: 8.0

DOMAINS¶

Type: array

Default: No Default

DOMAIN_PRINT¶

Do print the domains?

Type: boolean

Default: false

DOMAIN_PRINT_EXIT¶

Do exit after printing the domains?

Type: boolean

Default: false

E_CONVERGENCE¶

Convergence criterion for energy (change). See Table// Post-SCF Convergence for default convergence// criteria for different calculation types.

Type: conv double

Default: 1e-6

FOCK_TOLERANCE¶

Minimum absolute value below which parts of the Fock matrix are skipped.

Type: conv double

Default: 1e-2

INTS_TOLERANCE¶

Minimum absolute value below which integrals are neglected.

Type: conv double

Default: 1e-7

LOCAL¶

Do simulate the effects of local correlation techniques?

Type: boolean

Default: false

LOCAL_AMPS_PRINT_CUTOFF¶

Cutoff value for printing local amplitudes

Type: double

Default: 0.60

LOCAL_CPHF_CUTOFF¶

Cutoff value for local-coupled-perturbed-Hartree-Fock

Type: double

Default: 0.10

LOCAL_CUTOFF¶

Localization cutoff

Type: double

Default: 0.02

LOCAL_GHOST¶

Type: integer

Default: -1

LOCAL_METHOD¶

Type of local-CIS scheme to be simulated. WERNER selects the method// developed by H.-J. Werner and co-workers, and AOBASIS selects the method// developed by G.E. Scuseria and co-workers.

Type: string

Possible Values: AOBASIS, WERNER

Default: WERNER

LOCAL_PAIRDEF¶

Definition of local pair domains, default is BP, Boughton-Pulay.

Type: string

Possible Values: BP, RESPONSE

Default: BP

LOCAL_WEAKP¶

Desired treatment of “weak pairs” in the local-CIS method. A value of// NEGLECT ignores weak pairs entirely. A value of NONE treats weak pairs in// the same manner as strong pairs. A value of MP2 uses second-order perturbation// theory to correct the local-CIS energy computed with weak pairs ignored.

Type: string

Possible Values: MP2, NEGLECT, NONE

Default: MP2

MAXITER¶

Maximum number of iterations

Type: integer

Default: 50

MEMORY¶

The amount of memory available (in Mb)

Type: integer

Default: 2000

MP2_AMPS_PRINT¶

Do print the MP2 amplitudes which are the starting guesses for RHF and UHF reference functions?

Type: boolean

Default: false

MP2_OS_SCALE¶

The scale factor used for opposite-spin pairs in SCS computations

Type: double

Default: 6.0/5.0

MP2_SS_SCALE¶

The scale factor used for same-spin pairs in SCS computations

Type: double

Default: 1.0/3.0

NEGLECT_DISTANT_PAIR¶

Do neglect distant pairs?

Type: boolean

Default: true

NEW_TRIPLES¶

Do use new triples?

Type: boolean

Default: true

NUM_AMPS_PRINT¶

Number of important $t_1$ and $t_2$ amplitudes to print

Type: integer

Default: 10

PAIR_ENERGIES_PRINT¶

Do print MP2 and CCSD pair energies for RHF references?

Type: boolean

Default: false

PROPERTY¶

The response property desired. Acceptable values are POLARIZABILITY (default) for dipole-polarizabilities, ROTATION for specific rotations, ROA for Raman Optical Activity, and ALL for all of the above.

Type: string

Possible Values: POLARIZABILITY, ROTATION, MAGNETIZABILITY, ROA, ALL

Default: POLARIZABILITY

REFERENCE¶

Reference wavefunction type

Type: string

Possible Values: RHF

Default: RHF

RESTART¶

Do restart the coupled-cluster iterations from old $t_1$ and $t_2$ amplitudes? For geometry optimizations, Brueckner calculations, etc. the iterative solution of the CC amplitude equations may benefit considerably by reusing old vectors as initial guesses. Assuming that the MO phases remain the same between updates, the CC codes will, by default, re-use old vectors, unless the user sets RESTART = false.

Type: boolean

Default: true

ROOTS_PER_IRREP¶

The number of electronic states to computed, per irreducible// representation

Type: array

Default: No Default

R_CONVERGENCE¶

Convergence criterion for T2 amplitudes (RMS change).

Type: conv double

Default: 1e-5

SCREEN_INTS¶

Do screen integrals?

Type: boolean

Default: false

SCS¶

Do spin-component-scaled MP2 (SCS-MP2)?

Type: boolean

Default: false

SCSN_MP2¶

Do SCS-MP2 with parameters optimized for nucleic acids?

Type: boolean

Default: false

SCS_CCSD¶

Do spin-component-scaled CCSD

Type: boolean

Default: false

SCS_MP2¶

Do spin-component-scaled MP2 (SCS-MP2)?

Type: boolean

Default: false

SCS_N¶

Do SCS-MP2 with parameters optimized for nucleic acids?

Type: boolean

Default: false

SEMICANONICAL¶

Convert ROHF MOs to semicanonical MOs

Type: boolean

Default: true

SPINADAPT_ENERGIES¶

Do print spin-adapted pair energies?

Type: boolean

Default: false

T2_COUPLED¶

Type: boolean

Default: false

T3_WS_INCORE¶

Do build W intermediates required for cc3 in core memory?

Type: boolean

Default: false

Expert¶

AO_BASIS¶

The algorithm to use for the $\left<VV||VV\right>$ terms If AO_BASIS is NONE, the MO-basis integrals will be used; if AO_BASIS is DISK, the AO-basis integrals stored on disk will be used; if AO_BASIS is DIRECT, the AO-basis integrals will be computed on the fly as necessary. NB: The DIRECT option is not fully implemented and should only be used by experts. Default is NONE. Note: The developers recommend use of this keyword only as a last resort because it significantly slows the calculation. The current algorithms for handling the MO-basis four-virtual-index integrals have been significantly improved and are preferable to the AO-based approach.

Type: string

Possible Values: NONE, DISK, DIRECT

Default: NONE

FORCE_RESTART¶

Do restart the coupled-cluster iterations even if MO phases are screwed up?

Type: boolean

Default: false

WFN¶

Wavefunction type

Type: string

Default: LMP2

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