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(June 30, 2021)

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

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

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

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

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:

None

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 $n$th state.

RECOMMENDATION:

Check to see that the states do not change order during an optimization, due
to state crossings.

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

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

Defines a custom amplitude guess vector in SF-XCIS method.

TYPE:

INTEGER

DEFAULT:

0

OPTIONS:

$n$
builds a guess amplitude with an $\alpha $-hole in the $n$th orbital
(requires SFX_AMP_VIR_B).

RECOMMENDATION:

Only use when default guess is not satisfactory.

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 $\beta $-particle in the $n$th orbital
(requires SFX_AMP_OCC_A).

RECOMMENDATION:

Only use when default guess is not satisfactory.

XCIS

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_RPA

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 (requires ROHF ground state).

RECOMMENDATION:

None