OCC¶
Performs orbital-optimized MPn and CC computations and conventional MPn computations.
General¶
CACHELEVEL¶
Caching level for libdpd governing the storage of amplitudes, integrals, and intermediates in the CC procedure. A value of 0 retains no quantities in cache, while a level of 6 attempts to store all quantities in cache. For particularly large calculations, a value of 0 may help with certain types of memory problems. The default is 2, which means that all four-index quantities with up to two virtual-orbital indices (e.g., \(\langle ij | ab \rangle\) integrals) may be held in the cache.
- Type: integer
- Default: 2
CCL_ENERGY¶
Do compute CC Lambda energy? In order to this option to be valid one should use “TPDM_ABCD_TYPE = COMPUTE” * option.
- Type: boolean
- Default: false
CC_DIIS_MAX_VECS¶
Maximum number of vectors used in amplitude DIIS
- Type: integer
- Default: 6
CC_DIIS_MIN_VECS¶
Minimum number of vectors used in amplitude DIIS
- Type: integer
- Default: 2
CC_MAXITER¶
Maximum number of iterations to determine the amplitudes
- Type: integer
- Default: 50
CEPA_OS_SCALE¶
CEPA opposite-spin scaling value from SCS-CCSD
- Type: double
- Default: 1.27
CEPA_SOS_SCALE¶
CEPA Spin-opposite scaling (SOS) value
- Type: double
- Default: 1.3
CEPA_SS_SCALE¶
CEPA same-spin scaling value from SCS-CCSD
- Type: double
- Default: 1.13
CEPA_TYPE¶
CEPA type such as CEPA0, CEPA1 etc. currently we have only CEPA0.
- Type: string
- Possible Values: CEPA0
- Default: CEPA0
DO_LEVEL_SHIFT¶
Do apply level shifting?
- Type: boolean
- Default: true
DO_SCS¶
Do perform spin-component-scaled OMP2 (SCS-OMP2)? In all computation, SCS-OMP2 energy is computed automatically. However, in order to perform geometry optimizations and frequency computations with SCS-OMP2, one needs to set ‘DO_SCS’ to true
- Type: boolean
- Default: false
DO_SOS¶
Do perform spin-opposite-scaled OMP2 (SOS-OMP2)? In all computation, SOS-OMP2 energy is computed automatically. However, in order to perform geometry optimizations and frequency computations with SOS-OMP2, one needs to set ‘DO_SOS’ to true
- Type: boolean
- Default: false
E3_SCALE¶
Scaling value for 3rd order energy correction (S. Grimme, Vol. 24, pp. 1529, J. Comput. Chem.)
- Type: double
- Default: 0.25
EA_POLES¶
Do compute OCC poles for electron affinities? Only valid for OMP2.
- Type: boolean
- Default: false
EKT_EA¶
Do compute virtual orbital energies based on extended Koopmans’ theorem?
- Type: boolean
- Default: false
EKT_IP¶
Do compute occupied orbital energies based on extended Koopmans’ theorem?
- Type: boolean
- Default: false
EP_EA_POLES¶
Do compute EP-OCC poles for electron affinities? Only valid for OMP2.
- Type: boolean
- Default: false
EP_IP_POLES¶
Do compute EP-OCC poles for ionization potentials? Only valid OMP2.
- Type: boolean
- Default: false
EP_MAXITER¶
Maximum number of electron propagator iterations.
- Type: integer
- Default: 30
E_CONVERGENCE¶
Convergence criterion for energy. See Table Post-SCF Convergence for default convergence criteria for different calculation types.
- Type: conv double
- Default: 1e-6
IP_POLES¶
Do compute OCC poles for ionization potentials? Only valid OMP2.
- Type: boolean
- Default: false
LEVEL_SHIFT¶
Level shift to aid convergence
- Type: double
- Default: 0.02
LINEQ_SOLVER¶
The solver will be used for simultaneous linear equations.
- Type: string
- Possible Values: CDGESV, FLIN, POPLE
- Default: CDGESV
MAX_MOGRAD_CONVERGENCE¶
Convergence criterion for maximum orbital gradient
- Type: conv double
- Default: 1e-3
MOGRAD_DAMPING¶
Damping factor for the orbital gradient (Rendell et al., JCP, vol. 87, pp. 5976, 1987)
- Type: double
- Default: 1.0
MO_DIIS_NUM_VECS¶
Number of vectors used in orbital DIIS
- Type: integer
- Default: 6
MO_MAXITER¶
Maximum number of iterations to determine the orbitals
- Type: integer
- Default: 50
MO_READ¶
Do read coefficient matrices from external files of a previous OMP2 or OMP3 computation?
- Type: boolean
- Default: false
MO_STEP_MAX¶
Maximum step size in orbital-optimization procedure
- Type: double
- Default: 0.5
MO_WRITE¶
Do write coefficient matrices to external files for direct reading MOs in a subsequent job?
- Type: boolean
- Default: false
MP2_OS_SCALE¶
MP2 opposite-spin scaling value
- Type: double
- Default: 6.0
MP2_SOS_SCALE¶
MP2 Spin-opposite scaling (SOS) value
- Type: double
- Default: 1.3
MP2_SOS_SCALE2¶
Spin-opposite scaling (SOS) value for optimized-MP2 orbitals
- Type: double
- Default: 1.2
MP2_SS_SCALE¶
MP2 same-spin scaling value
- Type: double
- Default: 1.0
OCC_ORBS_PRINT¶
Do print OCC orbital energies?
- Type: boolean
- Default: false
OPT_METHOD¶
The optimization algorithm. Modified Steepest-Descent (MSD) takes a Newton-Raphson (NR) step with a crude approximation to diagonal elements of the MO Hessian. The ORB_RESP option obtains the orbital rotation parameters by solving the orbital-reponse (coupled-perturbed CC) equations. Additionally, for both methods a DIIS extrapolation will be performed with the DO_DIIS = TRUE option.
- Type: string
- Possible Values: MSD, ORB_RESP
- Default: ORB_RESP
ORB_RESP_SOLVER¶
The algorithm will be used for solving the orbital-response equations. The LINEQ option create the MO Hessian and solve the simultaneous linear equations with method choosen by the LINEQ_SOLVER option. The PCG option does not create the MO Hessian explicitly, instead it solves the simultaneous equations iteratively with the preconditioned conjugate gradient method.
- Type: string
- Possible Values: PCG, LINEQ
- Default: PCG
ORTH_TYPE¶
The algorithm for orthogonalization of MOs
- Type: string
- Possible Values: GS, MGS
- Default: MGS
PCG_BETA_TYPE¶
Type of PCG beta parameter (Fletcher-Reeves or Polak-Ribiere).
- Type: string
- Possible Values: FLETCHER_REEVES, POLAK_RIBIERE
- Default: FLETCHER_REEVES
PCG_CONVERGENCE¶
Convergence criterion for residual vector of preconditioned conjugate gradient method.
- Type: conv double
- Default: 1e-6
PCG_MAXITER¶
Maximum number of preconditioned conjugate gradient iterations.
- Type: integer
- Default: 30
RMS_MOGRAD_CONVERGENCE¶
Convergence criterion for RMS orbital gradient. Default adjusts depending on E_CONVERGENCE
- Type: conv double
- Default: 1e-6
R_CONVERGENCE¶
Convergence criterion for amplitudes (residuals).
- Type: conv double
- Default: 1e-5
SCS_TYPE¶
Type of the SCS method
- Type: string
- Possible Values: SCS, SCSN, SCSVDW, SCSMI
- Default: SCS
SYMMETRIZE¶
Do symmetrize the GFM and OPDM in the EKT computations?
- Type: boolean
- Default: true
TPDM_ABCD_TYPE¶
How to take care of the TPDM VVVV-block. The COMPUTE option means it will be computed via an IC/OOC algorithm. The DIRECT option (default) means it will not be computed and stored, instead its contribution will be directly added to Generalized-Fock Matrix.
- Type: string
- Possible Values: DIRECT, COMPUTE
- Default: DIRECT
