DCFT¶
Performs Density Cumulant Functional Theory computations
General¶
ALGORITHM¶
The algorithm to use for the density cumulant and orbital updates in the DCFT energy computation. Two-step algorithm (default) is usually more efficient for small systems, but for large systems the simultaneous algorithm is recommended. In the cases where the convergence problems are encountered (especially for highly symmetric systems) QC algorithm can be used.
- Type: string
- Possible Values: TWOSTEP, SIMULTANEOUS, QC
- Default: TWOSTEP
AO_BASIS¶
Controls whether to avoid the AO->MO transformation of the two-electron integrals for the four-virtual case (<VV||VV>) by computing the corresponding terms in the AO basis. AO_BASIS = DISK algorithm reduces the memory requirements and can significantly reduce the cost of the energy computation if SIMULTANEOUS algorithm is used. For the TWOSTEP algorithm, however, AO_BASIS = DISK option is not recommended due to the extra I/O.
- Type: string
- Possible Values: NONE, DISK
- Default: NONE
DCFT_FUNCTIONAL¶
Chooses appropriate DCFT method
- Type: string
- Possible Values: DC-06, DC-12, CEPA0
- Default: DC-06
DIIS_START_CONVERGENCE¶
Value of RMS of the density cumulant residual and SCF error vector below which DIIS extrapolation starts. Same keyword controls the DIIS extrapolation for the solution of the response equations.
- Type: conv double
- Default: 1e-3
LAMBDA_MAXITER¶
Maximum number of density cumulant update micro-iterations per macro-iteration (for ALOGRITHM = TWOSTEP). Same keyword controls the maximum number of density cumulant response micro-iterations per macro-iteration for the solution of the response equations (for RESPONSE_ALOGRITHM = TWOSTEP)
- Type: integer
- Default: 50
MAXITER¶
Maximum number of the macro-iterations for both the energy and the solution of the response equations
- Type: integer
- Default: 40
QC_COUPLING¶
Controls whether to include the coupling terms in the DCFT electronic Hessian (for ALOGRITHM = QC only)
- Type: boolean
- Default: true
RESPONSE_ALGORITHM¶
The algorithm to use for the solution of the response equations for the analytic gradients and properties.
- Type: string
- Possible Values: TWOSTEP, SIMULTANEOUS
- Default: TWOSTEP
R_CONVERGENCE¶
Convergence criterion for the RMS of the residual vector in the density cumulant updates, as well as the solution of the density cumulant and orbital response equations. In the orbital updates controls the RMS of the SCF error vector
- Type: conv double
- Default: 1e-10
SCF_MAXITER¶
Maximum number of the orbital update micro-iterations per macro-iteration (for ALOGRITHM = TWOSTEP). Same keyword controls the maximum number of orbital response micro-iterations per macro-iteration for the solution of the response equations (for RESPONSE_ALOGRITHM = TWOSTEP)
- Type: integer
- Default: 50
Expert¶
CACHELEVEL¶
Controls how to cache quantities within the DPD library
- Type: integer
- Default: 2
DAMPING_PERCENTAGE¶
The amount (percentage) of damping to apply to the orbital update procedure: 0 will result in a full update, 100 will completely stall the update. A value around 20 (which corresponds to 20% of the previous iteration’s density being mixed into the current iteration) can help in cases where oscillatory convergence is observed.
- Type: double
- Default: 0.0
DCFT_GUESS¶
Whether to read the orbitals from a previous computation, or to compute an MP2 guess
- Type: string
- Possible Values: CC, BCC, MP2
- Default: MP2
DIIS_MAX_VECS¶
Maximum number of error vectors stored for DIIS extrapolation
- Type: integer
- Default: 6
DIIS_MIN_VECS¶
Minimum number of error vectors stored for DIIS extrapolation
- Type: integer
- Default: 3
IGNORE_TAU¶
Controls whether to ignore terms containing non-idempotent contribution to OPDM or not (for debug puproses only). For practical applications only the default must be used
- Type: boolean
- Default: false
INTS_TOLERANCE¶
Minimum absolute value below which integrals are neglected
- Type: conv double
- Default: 1e-14
LOCK_OCC¶
Controls whether to force the occupation to be that of the SCF guess. For practical applications only the default must be used
- Type: boolean
- Default: true
MO_RELAX¶
Controls whether to relax the orbitals during the energy computation or not (for debug puproses only). For practical applications only the default must be used
- Type: boolean
- Default: true
RELAX_GUESS_ORBITALS¶
Controls whether to relax the guess orbitals by taking the guess density cumulant and performing orbital update on the first macroiteration (for ALOGRITHM = TWOSTEP only)
- Type: boolean
- Default: false
RELAX_TAU¶
Controls whether to relax tau during the cumulant updates or not
- Type: boolean
- Default: true
STABILITY_ADD_VECTORS¶
The number of vectors that can be added simultaneously into the subspace for Davidson’s diagonalization in stability check
- Type: integer
- Default: 20
STABILITY_AUGMENT_SPACE_TOL¶
The value of the rms of the residual in Schmidt orthogonalization which is used as a threshold for augmenting the vector subspace in stability check
- Type: conv double
- Default: 0.1
STABILITY_CHECK¶
Performs stability analysis of the DCFT energy
- Type: boolean
- Default: false
STABILITY_CONVERGENCE¶
Controls the convergence of the Davidson’s diagonalization in stability check
- Type: conv double
- Default: 1e-4
STABILITY_MAX_SPACE_SIZE¶
The maximum size of the subspace for the stability check. The program will terminate if this parameter is exceeded and the convergence (STABILITY_CONVERGENCE) is not satisfied
- Type: integer
- Default: 200
STABILITY_N_EIGENVALUES¶
The number of Hessian eigenvalues computed during the stability check
- Type: integer
- Default: 3
STABILITY_N_GUESS_VECTORS¶
The number of guess vectors used for Davidson’s diagonalization in stability check
- Type: integer
- Default: 20
TIKHONOW_OMEGA¶
The shift applied to the denominator in the density cumulant update iterations
- Type: double
- Default: 0.0