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
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.
| BASIS | BASIS_LIN_DEP_THRESH |
| EXCHANGE | CORRELATION |
| ECP | JOBTYPE |
| METHOD | PURECART |
| 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 |
| S2THRESH |
| CORRELATION | EXCHANGE |
| FAST_XC | INC_DFT |
| INCDFT_DENDIFF_THRESH | INCDFT_GRIDDIFF_THRESH |
| INCDFT_DENDIFF_VARTHRESH | INCDFT_GRIDDIFF_VARTHRESH |
| XC_GRID | XC_SMART_GRID |
| 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 |
| S2THRESH |
| AO2MO_DISK | CD_ALGORITHM |
| CORE_CHARACTER | CORRELATION |
| MEM_STATIC | MEM_TOTAL |
| N_FROZEN_CORE | N_FROZEN_VIRTUAL |
| PRINT_CORE_CHARACTER |
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 |
| 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 |
| 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 |
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 |