7.8.1 Job Control

NOCIS
       Requests a NOCIS/STEX/1C-NOCIS/EA-TDDFT calculation.
TYPE:
       LOGICAL
DEFAULT:
       FALSE
OPTIONS:
       FALSE Do not run these methods. TRUE Run one of these methods, options controlled in $nocis.
RECOMMENDATION:
       None

NUM_REF
       Sets the number of reference orbitals in a NOCIS/STEX/1C-NOCIS/EA-TDDFT calculation.
INPUT SECTION: $nocis
TYPE:
       INTEGER
DEFAULT:
       NONE
OPTIONS:
       $n$ Positive integer
RECOMMENDATION:
       Set according to the number of consecutive orbitals of interest for the calculation. For example, for the oxygen K-edge in CO${}_2$, the number of references would be 2 (two oxygen 1s orbitals), whereas for the carbon K-edge it would be 1 (one carbon 1s).

ORB_OFFSET
       Determines the starting orbital for a NOCIS/STEX/1C-NOCIS/EA-TDDFT calculation.
INPUT SECTION: $nocis
TYPE:
       INTEGER
DEFAULT:
       NONE
OPTIONS:
       $n$ Positive integer
RECOMMENDATION:
       Set according to the first orbital of interest in the system in question. For example, this would be set to 0 for the oxygen K-edge in CO${}_2$ because the two O(1s) orbitals lie below the C(1s), so for the carbon K-edge this would be set to 2.

LOCALIZE_ORBITALS
       Choose which core orbitals to localize with the Boys objective function.
INPUT SECTION: $nocis
TYPE:
       INTEGER
DEFAULT:
       $-1$ for NUM_REF = 1 and equal to NUM_REF otherwise.
OPTIONS:
       $n$ Integer, normally positive.
RECOMMENDATION:
       Set to $-1$ to skip Boys localization entirely, or set to a value greater than NUM_REF to include more orbitals in the preliminary localization, otherwise use the default.

SUBSYSTEM_ATOMS
       Choose which atoms to consider for an EA-TDDFT calculation.
INPUT SECTION: $nocis
TYPE:
       INTEGER
DEFAULT:
       NONE
OPTIONS:
       List of integers delimited by spaces: $ijk$…
RECOMMENDATION:
       Use only if excitations out of a particular subset of atoms is of interest and the definition of ORB_OFFSET and NUM_REF is nontrivial. This is an expert option, and should only be used in specific situations such as isolating the oxygen K-edge of all water molecules at the air/water interface.

DSCF_ALGORITHM
       Sets the $\mathrm{\Delta }$SCF algorithm to be used in the optimization of the core-ionized reference determinants.
INPUT SECTION: $nocis
TYPE:
       STRING
DEFAULT:
       MOM
OPTIONS:
       MOM, IMOM, STEP, or STEP_MOM
RECOMMENDATION:
       Use MOM unless convergence issues arise. IMOM occasionally provides improved convergence, but the combination of STEP and MOM used by the STEP_MOM option is particularly robust. In rare cases, STEP may be necessary, but this is not recommended as the number of SCF cycles required is quite large. If STEP_MOM is requested, the option STEP_MOM_START must also be set.

STEP_MOM_START
       Sets the SCF cycle on which the STEP algorithm stops and the MOM algorithm starts.
INPUT SECTION: $nocis
TYPE:
       INTEGER
DEFAULT:
       5
OPTIONS:
       $n$ Positive integer.
RECOMMENDATION:
       For best results, set such that STEP reaches a convergence threshold of at least ${10}^{-4}$ a.u. before switching to MOM, but if MOM continues to collapse or oscillate, then wait until tighter convergence is achieved to switch algorithms.

REF_SCF_ALGORITHM
       Sets the SCF algorithm for the core-ion reference calculations.
INPUT SECTION: $nocis
TYPE:
       STRING
DEFAULT:
       DIIS
OPTIONS:
       DIIS, GDM, GDM_LS, SGM, or SGM_LS
RECOMMENDATION:
       Use DIIS for MOM, IMOM, STEP, or STEP_MOM calculations, but if these algorithms are not providing satisfactory convergence to the desired core-ion state, this can be set to SGM or SGM_LS.

REF_SCF_CONVERGENCE
       Sets SCF convergence threshold for the core-ion reference calculations.
INPUT SECTION: $nocis
TYPE:
       INTEGER
DEFAULT:
       Same as SCF_CONVERGENCE in $rem
OPTIONS:
       $n$ Positive integer
RECOMMENDATION:
       None

REF_SCF_GUESS
       Initial guess for core-ion reference calculations.
INPUT SECTION: $nocis
TYPE:
       STRING
DEFAULT:
       Koopman
OPTIONS:
       Read (the Koopmans guess is automatically used if no option is specified)
RECOMMENDATION:
       The default core-ion guess is generated by removing an electron from the core orbital using the ground-state MO coefficients (Koopmans guess). Alternatively, when convergence issues arise it may be useful to run an EA-TDDFT job with a different functional (i.e., LDA or GGA), then read the converged core-ion orbitals into a subsequent EA-TDDFT job with the functional of interest (i.e., a range-separated hybrid).

EA_TDA
       Invokes EA-TDDFT within the Tamm-Dancoff approximation.
INPUT SECTION: $nocis
TYPE:
       NONE
DEFAULT:
       NONE
OPTIONS:
       The presence of this keyword will activate EA_TDA.
RECOMMENDATION:
       This is the most cost-effective form of the EA-TDDFT equations and has almost no effect on results for K-edge XAS.

EA_RPA
       Solves the full EA-TDDFT equations.
INPUT SECTION: $nocis
TYPE:
       NONE
DEFAULT:
       NONE
OPTIONS:
       The presence of this keyword will activate EA_RPA.
RECOMMENDATION:
       No recommendation.

SINGLETS
       Compute only singlets.
INPUT SECTION: $nocis
TYPE:
       NONE
DEFAULT:
       NONE
OPTIONS:
       The presence of this keyword without the Triplets keyword will compute singlets without computing triplets.
RECOMMENDATION:
       No recommendation.

TRIPLETS
       Compute only triplets.
INPUT SECTION: $nocis
TYPE:
       NONE
DEFAULT:
       NONE
OPTIONS:
       The presence of this keyword without the Singlets keyword will compute triplets without computing singlets.
RECOMMENDATION:
       No recommendation.

N_ROOTS
       Sets the number of roots to print.
INPUT SECTION: $nocis
TYPE:
       INTEGER
DEFAULT:
       All
OPTIONS:
       $n$ where
RECOMMENDATION:
       No recommendation. Beware that unlike CIS/TDDFT jobs this keyword only prints fewer roots, but the entirety of the Hamiltonian is still diagonalized via direct diagonalization.

PRINT_NTOS
       Prints natural transition orbitals to cube files for each root that is printed via the N_ROOTS keyword.
INPUT SECTION: $nocis
TYPE:
       NONE
DEFAULT:
       NONE
OPTIONS:
       The presence of this keyword automatically generates all NTOs (default), or N_ROOTS NTOs.
RECOMMENDATION:
       No recommendation, but one should be sure to also include a $plots section with appropriate details such that the cube files can be generated.