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7.2 Uncorrelated Wave Function Methods

7.2.4 Job Control Options

(May 7, 2024)

Basic job control variables to run CIS and related methods are discussed in Section 7.2.4.1 and more advanced options are listed in Section 7.2.4.2.

7.2.4.1 Basic Job Control

CIS-type jobs are requested by setting the $rem variable EXCHANGE = HF and CORRELATION = NONE, as in a ground-state Hartree-Fock calculation, but then also specifying a number of excited-state roots using the $rem keyword CIS_N_ROOTS.

Note:  For RHF case, n singlets and n triplets will be computed, unless specified otherwise by using CIS_TRIPLETS and CIS_SINGLETS.

CIS_N_ROOTS

CIS_N_ROOTS
       Sets the number of CI-Singles (CIS) excited state roots to find.
TYPE:
       INTEGER
DEFAULT:
       0 Do not look for any excited states.
OPTIONS:
       n n>0 Looks for n CIS excited states.
RECOMMENDATION:
       None

CIS_SINGLETS

CIS_SINGLETS
       Solve for singlet excited states in RCIS calculations (ignored for UCIS).
TYPE:
       LOGICAL
DEFAULT:
       TRUE
OPTIONS:
       TRUE Solve for singlet states. FALSE Do not solve for singlet states.
RECOMMENDATION:
       None

CIS_TRIPLETS

CIS_TRIPLETS
       Solve for triplet excited states in RCIS calculations (ignored for UCIS).
TYPE:
       LOGICAL
DEFAULT:
       TRUE
OPTIONS:
       TRUE Solve for triplet states. FALSE Do not solve for triplet states.
RECOMMENDATION:
       None

CIS_STATE_DERIV

CIS_STATE_DERIV
       Sets CIS state for excited state optimizations and vibrational analysis.
TYPE:
       INTEGER
DEFAULT:
       0 Does not select any of the excited states.
OPTIONS:
       n Select the nth state.
RECOMMENDATION:
       Check to see that the states do not change order during an optimization, due to state crossings.

RPA

RPA
       Do an RPA calculation in addition to a CIS or TDDFT/TDA calculation.
TYPE:
       LOGICAL/INTEGER
DEFAULT:
       FALSE
OPTIONS:
       FALSE Do not do an RPA calculation. TRUE Do an RPA calculation. 2 Do an RPA calculation without running CIS or TDDFT/TDA first.
RECOMMENDATION:
       RPA = 2 is not available for restricted open-shell wavefunctions.

SPIN_FLIP

SPIN_FLIP
       Selects whether to perform a standard excited state calculation, or a spin-flip calculation. Spin multiplicity should be set to 3 for systems with an even number of electrons, and 4 for systems with an odd number of electrons.
TYPE:
       LOGICAL
DEFAULT:
       FALSE
OPTIONS:
       TRUE/FALSE
RECOMMENDATION:
       None

SPIN_FLIP_XCIS

SPIN_FLIP_XCIS
       Controls whether to do a SF-XCIS calculation.
TYPE:
       LOGICAL
DEFAULT:
       FALSE
OPTIONS:
       FALSE Do not do an SF-XCIS calculation. TRUE Do an SF-XCIS calculation (requires ROHF triplet ground state).
RECOMMENDATION:
       None

SFX_AMP_OCC_A

SFX_AMP_OCC_A
       Defines a custom amplitude guess vector in SF-XCIS method.
TYPE:
       INTEGER
DEFAULT:
       0
OPTIONS:
       n builds a guess amplitude with an α-hole in the nth orbital (requires SFX_AMP_VIR_B).
RECOMMENDATION:
       Only use when default guess is not satisfactory.

SFX_AMP_VIR_B

SFX_AMP_VIR_B
       Defines a user-specified amplitude guess vector in SF-XCIS method.
TYPE:
       INTEGER
DEFAULT:
       0
OPTIONS:
       n builds a guess amplitude with a β-particle in the nth orbital (requires SFX_AMP_OCC_A).
RECOMMENDATION:
       Only use when default guess is not satisfactory.

XCIS

XCIS
       Controls whether to do an XCIS calculation in addition to a CIS calculation.
TYPE:
       LOGICAL
DEFAULT:
       FALSE
OPTIONS:
       FALSE Do not do an XCIS calculation. TRUE Do an XCIS calculation (requires ROHF ground state).
RECOMMENDATION:
       None

SASF_CIS

SASF_CIS
       Controls whether to do an SA-SF-CIS/DFT calculation.
TYPE:
       LOGICAL
DEFAULT:
       FALSE
OPTIONS:
       FALSE Do not do an SA-SF-CIS/DFT calculation. TRUE Do an SA-SF-CIS/DFT calculation.
RECOMMENDATION:
       The SA-SF method requires a restricted open-shell ground-state calculation.

DFTCIS

DFTCIS
       Controls whether to do a DFT/CIS calculation.
TYPE:
       LOGICAL
DEFAULT:
       FALSE
OPTIONS:
       FALSE Do not do a DFT/CIS calculation. TRUE Do a DFT/CIS calculation.
RECOMMENDATION:
       None

DFTCIS_PARAMS

DFTCIS_PARAMS
       Selects what variant of DFT/CIS
TYPE:
       INTEGER
DEFAULT:
       0
OPTIONS:
       0 Do CIS 1 Do B3LYP/CIS 2 Do CAM-B3LYP/CIS
RECOMMENDATION:
       Requires DFTCIS to be set to 1 or 2.

7.2.4.2 Additional CIS Customization

Additional variables for fine-tuning CIS and related calculations are provided below.

N_FROZEN_CORE

N_FROZEN_CORE
       Controls the number of frozen core orbitals.
TYPE:
       INTEGER/STRING
DEFAULT:
       0 No frozen core orbitals.
OPTIONS:
       FC Frozen core approximation. n Freeze n core orbitals.
RECOMMENDATION:
       There is no computational advantage to using frozen core for CIS, and analytical derivatives are only available when no orbitals are frozen. It is helpful when calculating CIS(D) corrections (see Section 7.9).

N_FROZEN_VIRTUAL

N_FROZEN_VIRTUAL
       Controls the number of frozen virtual orbitals.
TYPE:
       INTEGER
DEFAULT:
       0 No frozen virtual orbitals.
OPTIONS:
       n Freeze n virtual orbitals.
RECOMMENDATION:
       There is no computational advantage to using frozen virtuals for CIS, and analytical derivatives are only available when no orbitals are frozen.

MAX_CIS_CYCLES

MAX_CIS_CYCLES
       Maximum number of CIS iterative cycles allowed.
TYPE:
       INTEGER
DEFAULT:
       30
OPTIONS:
       n User-defined number of cycles.
RECOMMENDATION:
       Default is usually sufficient.

MAX_CIS_SUBSPACE

MAX_CIS_SUBSPACE
       Maximum number of subspace vectors allowed in the CIS iterations
TYPE:
       INTEGER
DEFAULT:
       As many as required to converge all roots
OPTIONS:
       n User-defined number of subspace vectors
RECOMMENDATION:
       The default is usually appropriate, unless a large number of states are requested for a large molecule. The total memory required to store the subspace vectors is bounded above by 2nOV, where O and V represent the number of occupied and virtual orbitals, respectively. n can be reduced to save memory, at the cost of a larger number of CIS iterations. Convergence may be impaired if n is not much larger than CIS_N_ROOTS.

CIS_CONVERGENCE

CIS_CONVERGENCE
       CIS is considered converged when error is less than 10-CIS_CONVERGENCE
TYPE:
       INTEGER
DEFAULT:
       6 CIS convergence threshold 10-6
OPTIONS:
       n Corresponding to 10-n
RECOMMENDATION:
       Also controls convergence of the CPSCF equations.

CIS_DYNAMIC_MEM

CIS_DYNAMIC_MEM
       Controls whether to use static or dynamic memory in CIS and TDDFT calculations.
TYPE:
       LOGICAL
DEFAULT:
       FALSE
OPTIONS:
       FALSE Partly use static memory TRUE Fully use dynamic memory
RECOMMENDATION:
       The default control requires static memory (MEM_STATIC) sufficient to hold an array whose size grows by 2×OV×Nroots at each CIS iteration, where Nroots is the number of unconverged roots ( CIS_N_ROOTS). For a large calculation, one has to specify a large value for MEM_STATIC, which is not recommended (see Chapter 2). Therefore, it is recommended to use dynamic memory for large calculations.

CIS_RELAXED_DENSITY

CIS_RELAXED_DENSITY
       Use the relaxed CIS density for attachment/detachment density analysis as well as for for the general excited-state analysis of Section 10.2.11.
TYPE:
       LOGICAL
DEFAULT:
       FALSE
OPTIONS:
       FALSE Do not use the relaxed CIS density in analysis. TRUE Use the relaxed CIS density in analysis.
RECOMMENDATION:
       None

CIS_GUESS_DISK

CIS_GUESS_DISK
       Read the CIS guess from disk (previous calculation).
TYPE:
       LOGICAL
DEFAULT:
       FALSE
OPTIONS:
       FALSE Create a new guess. TRUE Read the guess from disk.
RECOMMENDATION:
       Requires a guess from previous calculation.

CIS_GUESS_DISK_TYPE

CIS_GUESS_DISK_TYPE
       Determines the type of guesses to be read from disk
TYPE:
       INTEGER
DEFAULT:
       Nil
OPTIONS:
       0 Read triplets only 1 Read triplets and singlets 2 Read singlets only
RECOMMENDATION:
       Must be specified if CIS_GUESS_DISK is TRUE.

STS_MOM

STS_MOM
       Control calculation of the transition moments between excited states in CIS and TDDFT calculations (including spin-flip variants).
TYPE:
       LOGICAL
DEFAULT:
       FALSE
OPTIONS:
       FALSE Do not calculate state-to-state transition moments. TRUE Do calculate state-to-state transition moments.
RECOMMENDATION:
       When set to true requests the state-to-state dipole transition moments for all pairs of excited states and for each excited state with the ground state. This is not available for restricted open-shell wavefunctions.

CIS_MOMENTS

CIS_MOMENTS
       Controls calculation of excited-state (CIS or TDDFT) multipole moments.
TYPE:
       LOGICAL
DEFAULT:
       FALSE
OPTIONS:
       FALSE Do not calculate excited-state moments. TRUE Calculate moments for each excited state.
RECOMMENDATION:
       Set to TRUE if excited-state moments are desired. (This is a trivial additional calculation.) The MULTIPOLE_ORDER controls how many multipole moments are printed. This option is not available for spin-flip methods.