# 7.2.8 CIS Job Customization

(June 30, 2021)

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 Sec. 7.9).

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
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
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 is considered converged when error is less than $10^{-\mathrm{CIS\_CONVERGENCE}}$
TYPE:
INTEGER
DEFAULT:
6 CIS convergence threshold 10${}^{-6}$
OPTIONS:
$n$ Corresponding to $10^{-n}$
RECOMMENDATION:
None

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 $2\times OV\times N_{\text{roots}}$ at each CIS iteration, where $N_{\text{roots}}$ is the number of unconverged roots ($\leq$ 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
Use the relaxed CIS density for attachment/detachment density analysis as well as for for the general excited-state analysis of Section 10.2.6.
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
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
Determines the type of guesses to be read from disk
TYPE:
INTEGER
DEFAULT:
Nil
OPTIONS:
RECOMMENDATION:
Must be specified if CIS_GUESS_DISK is TRUE.

STS_MOM
Control calculation of the transition moments between excited states in the CIS and TDDFT calculations (including SF-CIS and SF-DFT).
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.

Note:  This option is not available for SF-XCIS.

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.