C.3 $rem Variable List

The general format of the $rem input for Q-Chem text input files is simply as follows:

$rem
   rem_variable   rem_option   [comment]
   rem_variable   rem_option   [comment]
$end

This input is not case sensitive. The following sections contain the names and options of available $rem variables for users. The format for describing each $rem variable is as follows:

REM_VARIABLE

A short description of what the variable controls

TYPE:

Defines the variable as either INTEGER, LOGICAL or STRING.

DEFAULT:

Describes Q-Chem’s internal default, if any exists.

OPTIONS:

Lists options available for the user

RECOMMENDATION:

Gives a quick recommendation.

C.3.1 General

BASIS	BASIS_LIN_DEP_THRESH
EXCHANGE	CORRELATION
ECP	JOBTYPE
METHOD	PURECART

C.3.2 SCF Control

BASIS2	BASISPROJTYPE
DIIS_PRINT	DIIS_SUBSPACE_SIZE
DIRECT_SCF	INCFOCK
MAX_DIIS_CYCLES	MAX_SCF_CYCLES
PSEUDO_CANONICAL	SCF_ALGORITHM
SCF_CONVERGENCE	SCF_FINAL_PRINT
SCF_GUESS	SCF_GUESS_MIX
SCF_GUESS_PRINT	SCF_PRINT
THRESH	THRESH_DIIS_SWITCH
UNRESTRICTED	VARTHRESH

C.3.3 DFT Options

CORRELATION	EXCHANGE
FAST_XC	INC_DFT
INCDFT_DENDIFF_THRESH	INCDFT_GRIDDIFF_THRESH
INCDFT_DENDIFF_VARTHRESH	INCDFT_GRIDDIFF_VARTHRESH
XC_GRID	XC_SMART_GRID

C.3.4 Large Molecules

CFMM_ORDER	DIRECT_SCF
EPAO_ITERATE	EPAO_WEIGHTS
GRAIN	INCFOCK
INTEGRAL_2E_OPR	INTEGRALS_BUFFER
LIN_K	MEM_STATIC
MEM_TOTAL	METECO
OMEGA	PAO_ALGORITHM
PAO_METHOD	THRESH
VARTHRESH	RI_J
RI_K	ARI
ARI_R0	ARI_R1

C.3.5 Correlated Methods

AO2MO_DISK	CD_ALGORITHM
CORE_CHARACTER	CORRELATION
MEM_STATIC	MEM_TOTAL
N_FROZEN_CORE	N_FROZEN_VIRTUAL
PRINT_CORE_CHARACTER

C.3.6 Correlated Methods Handled by CCMAN and CCMAN2

Most of these $rem variables that start CC_.

These are relevant for CCSD and other CC methods (OD, VOD, CCD, QCCD, CCVB-SD, etc).

CC_CANONIZE	CC_RESTART_NO_SCF
CC_T_CONV	CC_DIIS_SIZE
CC_DIIS_FREQ	CC_DIIS_START
CC_DIIS_MAX_OVERLAP	CC_DIIS_MIN_OVERLAP
CC_RESTART	CC_SAVEAMPL

These options are only relevant to methods involving orbital optimization (OOCD, VOD, QCCD, VQCCD):

CC_MP2NO_GUESS	CC_MP2NO_GRAD
CC_DIIS	CC_DIIS12_SWITCH
CC_THETA_CONV	CC_THETA_GRAD_CONV
CC_THETA_STEPSIZE	CC_RESET_THETA
CC_THETA_GRAD_THRESH	CC_HESS_THRESH
CC_ED_CCD	CC_QCCD_THETA_SWITCH
CC_PRECONV_T2Z	CC_PRECONV_T2Z_EACH
CC_PRECONV_FZ	CC_ITERATE_OV
CC_CANONIZE_FREQ	CC_CANONIZE_FINAL

Properties and optimization:

CC_REF_PROP	CC_REF_PROP_TE
CC_FULLRESPONSE

C.3.7 Perfect pairing, Coupled cluster valence bond, and related methods

CCVB_METHOD	CCVB_GUESS
GVB_N_PAIRS	GVB_LOCAL
GVB_ORB_MAX_ITER	GVB_RESTART
GVB_ORB_CONV	GVB_ORB_SCALE
GVB_AMP_SCALE	GVB_DO_SANO
GVB_PRINT

C.3.8 Excited States: CIS, TDDFT, SF-XCIS and SOS-CIS(D)

CIS_CONVERGENCE	CIS_GUESS_DISK
CIS_GUESS_DISK_TYPE	CIS_N_ROOTS
CIS_RELAXED_DENSITY	CIS_SINGLETS
CIS_STATE_DERIV	CIS_TRIPLETS
MAX_CIS_CYCLES	RPA
XCIS	SPIN_FLIP_XCIS

C.3.9 Excited States: EOM-CC and CI Methods

Those are keywords relevant to EOM-CC and CI methods handled by CCMAN/CCMAN2. Most of these $rem variables that start CC_ and EOM_.

EOM_DAVIDSON_CONVERGENCE	EOM_DAVIDSON_MAXVECTORS
EOM_DAVIDSON_THRESHOLD	EOM_DAVIDSON_MAX_ITER
EOM_NGUESS_DOUBLES	EOM_NGUESS_SINGLES
EOM_DOEXDIAG	EOM_PRECONV_DOUBLES
EOM_PRECONV_SINGLES	EOM_PRECONV_SD
EOM_IPEA_FILTER	EOM_FAKE_IPEA
CC_REST_AMPL	CC_REST_TRIPLES
CC_EOM_PROP	CC_TRANS_PROP
CC_STATE_TO_OPT	CC_EOM_PROP
CC_EOM_PROP_TE	CC_FULLRESPONSE

C.3.10 Geometry Optimizations

CIS_STATE_DERIV	FDIFF_STEPSIZE
GEOM_OPT_COORDS	GEOM_OPT_DMAX
GEOM_OPTHESSIAN	GEOM_OPT_LINEAR_ANGLE
GEOM_OPT_MAX_CYCLES	GEOM_OPT_MAX_DIIS
GEOM_OPT_MODE	GEOM_OPT_PRINT
GEOM_OPTSYMFLAG	GEOM_OPT_PRINT
GEOM_OPTTOL_ENERGY	GEOM_OPT_TOL_DISPLACEMENT
GEOM_OPT_TOL_ENERGY	GEOM_OPT_TOL_GRADIENT
GEOMP_OPT_UPDATE	IDERIV
JOBTYPE	SCF_GUESS_ALWAYS
CC_STATE_TO_OPT

C.3.11 Vibrational Analysis

DORAMAN	CPSCF_NSEG
FDIFF_STEPSIZE	IDERIV
ISOTOPES	JOBTYPE
VIBMAN_PRINT	ANHAR
VCI	FDIFF_DER
MODE_COUPLING	IGNORE_LOW_FREQ
FDIFF_STEPSIZE_QFF

C.3.12 Reaction Coordinate Following

JOBTYPE	RPATH_COORDS
RPATH_DIRECTION	RPATH_MAX_CYCLES
RPATH_MAX_STEPSIZE	RPATH_PRINT
RPATH_TOL_DISPLACEMENT

C.3.13 NMR Calculations

D_CPSCF_PERTNUM	D_SCF_CONV_1
D_SCF_CONV_2	D_SCF_DIIS
D_SCF_MAX_1	D_SCF_MAX_2
JOBTYPE

C.3.14 Wave function Analysis and Molecular Properties

CHEMSOL	CHEMSOL_EFIELD
CHEMSOL_NN	CHEM_SOL_PRINT
CIS_RELAXED_DENSITY	IGDESP
INTRACULE	MAGNET
MULTIPOLE_ORDER	NBO
POP_MULLIKEN	PRINT_DIST_MATRIX
PRINT_ORBITALS	READ_VDW
RESPONSE	SOLUTE_RADIUS
SOLVENT_DIELECTRIC	STABILITY_ANALYSIS
WAVEFUNCTION_ANALYSIS	WRITE_WFN

C.3.15 Symmetry

CC_SYMMETRY
SYM_IGNORE	SYMMETRY
SYMMETRY_DECOMPOSITION	SYM_TOL

C.3.16 Printing Options

CC_PRINT	CHEMSOL_PRINT
DIIS_PRINT	GEOM_OPT_PRINT
MOM_PRINT	PRINT_CORE_CHARACTER
PRINT_DIST_MATRIX	PRINT_GENERAL_BASIS
PRINT_ORBITALS	RPATH_PRINT
SCF_FINAL_PRINT	SCF_GUESS_PRINT
SCF_PRINT	VIBMAN_PRINT
WRITE_WFN

C.3.17 Resource Control

MEM_TOTAL	MEM_STATIC
AO2MO_DISK	CC_MEMORY
INTEGRALS_BUFFER	MAX_SUB_FILE_NUM
DIRECT_SCF