CCEOM

Performs equation-of-motion (EOM) coupled cluster excited state computations.

General

ABCD

Type of ABCD algorithm will be used

  • Type: string
  • Possible Values: NEW, OLD
  • Default: NEW

CACHELEVEL

Caching 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 quantities with up to two virtual-orbital indices (e.g., \(\left\langle ij | ab \right\rangle\) integrals) may be held in the cache.

  • Type: integer
  • Default: 2

CACHETYPE

The criterion used to retain/release cached data

  • Type: string
  • Possible Values: LOW, LRU
  • Default: LRU

CC3_FOLLOW_ROOT

Do turn on root following for CC3

CC_NUM_THREADS

Number of threads

  • Type: integer
  • Default: 1

COLLAPSE_WITH_LAST

Do collapse with last vector?

COMPLEX_TOLERANCE

Complex tolerance applied in CCEOM computations

EOM_GUESS

Specifies a set of single-excitation guess vectors for the EOM-CC procedure. If EOM_GUESS = SINGLES, the guess will be taken from the singles-singles block of the similarity-transformed Hamiltonian, Hbar. If EOM_GUESS = DISK, guess vectors from a previous computation will be read from disk. If EOM_GUESS = INPUT, guess vectors will be specified in user input. The latter method is not currently available.

  • Type: string
  • Possible Values: SINGLES, DISK, INPUT
  • Default: SINGLES

EOM_REFERENCE

Reference wavefunction type for EOM computations

  • Type: string
  • Possible Values: RHF, ROHF, UHF
  • Default: RHF

E_CONVERGENCE

Convergence criterion for excitation energy (change) in the Davidson algorithm for CC-EOM. See Table Post-SCF Convergence for default convergence criteria for different calculation types.

FULL_MATRIX

Do use full effective Hamiltonian matrix?

LOCAL

Do simulate the effects of local correlation techniques?

LOCAL_CUTOFF

Value (always between one and zero) for the Broughton-Pulay completeness check used to contruct orbital domains for local-CC calculations. See J. Broughton and P. Pulay, J. Comp. Chem. 14, 736-740 (1993) and C. Hampel and H.-J. Werner, J. Chem. Phys. 104, 6286-6297 (1996).

  • Type: double
  • Default: 0.02

LOCAL_DO_SINGLES

LOCAL_FILTER_SINGLES

Do apply local filtering to singles amplitudes?

LOCAL_GHOST

Permit ghost atoms to hold projected atomic orbitals to include in the virtual space in local-EOM-CCSD calculations

  • Type: integer
  • Default: -1

LOCAL_METHOD

Type of local-CCSD 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 (currently inoperative).

  • Type: string
  • Possible Values: WERNER, AOBASIS
  • Default: WERNER

LOCAL_PRECONDITIONER

Preconditioner will be used in local CC computations

  • Type: string
  • Possible Values: HBAR, FOCK
  • Default: HBAR

LOCAL_WEAKP

Desired treatment of “weak pairs” in the local-CCSD 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-CCSD energy computed with weak pairs ignored.

  • Type: string
  • Possible Values: NONE, MP2, NEGLECT
  • Default: NONE

MAXITER

Maximum number of iterations

  • Type: integer
  • Default: 80

NEW_TRIPLES

Do use new triples?

NUM_AMPS_PRINT

Number of important CC amplitudes to print

  • Type: integer
  • Default: 5

OVERLAP_CHECK

Report overlaps with old excited-state wave functions, if * available, and store current wave functions for later use.

PROP_ROOT

Root number (within its irrep) for computing properties. Defaults to highest root requested.

  • Type: integer
  • Default: 0

PROP_SYM

Symmetry of the state to compute properties. Defaults to last irrep for which states are requested.

  • Type: integer
  • Default: 1

REFERENCE

Reference wavefunction type

  • Type: string
  • Possible Values: RHF, ROHF, UHF
  • Default: RHF

RESTART_EOM_CC3

Do restart from on-disk?

RHF_TRIPLETS

Do form a triplet state from RHF reference?

ROOTS_PER_IRREP

Number of excited states per irreducible representation for EOM-CC and CC-LR calculations. Irreps denote the final state symmetry, not the symmetry of the transition.

  • Type: array
  • Default: No Default

R_CONVERGENCE

Convergence criterion for norm of the residual vector in the Davidson algorithm for CC-EOM.

SCHMIDT_ADD_RESIDUAL_TOLERANCE

Minimum absolute value above which a guess vector to a root is added to the Davidson algorithm in the EOM-CC iterative procedure.

SEMICANONICAL

Convert ROHF MOs to semicanonical MOs

SINGLES_PRINT

Do print information on the iterative solution to the single-excitation EOM-CC problem used as a guess to full EOM-CC?

SS_E_CONVERGENCE

Convergence criterion for excitation energy (change) in the Davidson algorithm for the CIS guess to CC-EOM.

SS_R_CONVERGENCE

Convergence criterion for norm of the residual vector in the Davidson algorithm for the CIS guess to CC-EOM.

SS_SKIP_DIAG

Do skip diagonalization of Hbar SS block?

SS_VECS_PER_ROOT

SS vectors stored per root

  • Type: integer
  • Default: 5

T3_WS_INCORE

Do build W intermediates required for eom_cc3 in core memory?

VECS_CC3

Vectors stored in CC3 computations

  • Type: integer
  • Default: 10

VECS_PER_ROOT

Vectors stored per root

  • Type: integer
  • Default: 12

Expert

EXCITATION_RANGE

The depth into the occupied and valence spaces from which one-electron excitations are seeded into the Davidson guess to the CIS (the default of 2 includes all single excitations between HOMO-1, HOMO, LUMO, and LUMO+1). This CIS is in turn the Davidson guess to the EOM-CC. Expand to capture more exotic excited states in the EOM-CC calculation

  • Type: integer
  • Default: 2

WFN

Wavefunction type

  • Type: string
  • Possible Values: EOM_CCSD, EOM_CC2, EOM_CC3
  • Default: EOM_CCSD